- -Splinter, to Leonardo
Though stern at certain times, Splinter is also a protective and affable parent, quirky master, and a Zen philosopher (he is very often seen in the Dojo meditating). Having lost a family once, he is very determined to train and protect his new one at all costs, though he grudgingly realizes that the Turtles are now at an age where he will have to, at some point, give them the freedom to make their own mistakes in the outside world....He is a ninja master at the height of his abilities - He is so in tune with the universe that he can literally feel it's vibrations, allowing him to project and sense energy, and, ocassionally, the intentions of others.
Originally a human named Hamato Yoshi, Splinter lived in Japan and studied ninjutsu alongside his best friend, Oroku Saki (later known as The Shredder). Yoshi's father found the young Saki as a baby, and raised him as Yoshi's brother. At some point, both men fell in love at the same time with the same woman, Tang Shen, which ended up sparking a bitter rivalry between them. Eventually, Tang Shen married Yoshi and gave birth to their daughter, Miwa. One night, Saki, mad with jealousy and hatred, attacked Yoshi in his home, intending to kill him. During the battle, the house caught fire and Saki mercilessly left Yoshi to die. While Yoshi survived the fire, Tang Shen did not, and their daughter, Miwa, had supposedly died as well.
Devastated, Hamato gave up his original name and left Japan for an eternity. Under the alias "Splinter", he came to live in New York City. One fateful day, he bought four baby turtles at a local pet store. As he was walking down the street, he bumped into a suspicious man, whom he curiously followed into an alley way. As Splinter watched the first man exchanging a strange canister of ooze with another, he stepped onto a passing rat that gave away his position. A fight ensued, and while Splinter was able to defeat the men (who were actually Kraang droids in disguise), the canister was broken. Splinter and his newly bought pet turtles were all covered in ooze and mutated instantly. He became a giant rat for the last thing he touched was a rat before his mutation.
For the following fifteen years, Splinter and the Turtles lived in hiding in the sewers under New York City. Taking them in as his sons and students, Splinter raised the turtles and trained them in the ways of Ninjutsu. When they turned fifteen, Splinter, though reluctant, allowed them to leave the lair for the very first time.
In Rise of the Turtles, Part 1, Splinter is seen telling the pivotal story of his mutation to the Turtles. It is revealed that he had also kept the canister of Mutagen that mutated them all as a charming souvenir. As a celebration of the Turtles' fifteenth 'birthday', Splinter, though reluctantly, allows them to explore the wondrous streets of New York City...
In Rise of the Turtles, Part 2, Splinter tells of his rivalry with The Shredder to a curious Leonardo, who wants to know if he can truly handle being the leader of his brothers. After the turtles rescued April, Leonardo asked Splinter if the reason that he made Leo the leader was because he had a true warrior spirit, Splinter actually reveals that the reason he made Leonardo the leader was because he asked, when questioned if any of the other brothers would have become leader if they asked first to which Splinter agreed, except for Michelangelo because he would think that would have been wrong.
In Turtle Temper, Splinter explains to a grumpy Raphael that anger can indeed jeopardize the people around you. Yet again, Splinter tells of his harsh past. He explains that his temper against The Shredder is what ultimately caused one of his own family members to get killed before his very eyes.
In New Friend, Old Enemy, Splinter only briefly appears when he recognizes a familiar move used by Leonardo in a sparring match with Raph (this move was taught by Mikey to Leonardo and the others). They quickly realize that Mikey's recently made friend, Chris Bradford, is one of The Shredder's deadly top henchmen.
In I Think His Name is Baxter Stockman, Splinter unexpectedly catches the Turtles misbehaving and skateboarding in the lair. He grounds them for a week, but they decide to sneak out against Splinter's will and encounter a lone man dressed in robotic armor named Baxter Stockman, whom is trying to break into a building to construct his revenge on those who fired him. At first, they defeat him easily, but the fight turns into much more than they expect....When Splinter learns that they betrayed him, he is not pleased very much at all - but he does give them some good advice on their situation with Stockman - "Never fight the armor, fight the man inside", is what he says.
In Metalhead, Splinter is able to convince Donatello (who is finding his own Bo staff to be relatively ineffective in combat) that Martial Arts can sometimes prove to be more effective than using robotic machines. Donnie indeed learns his lesson when his own creation, Metalhead, falls under the control of The Kraang and he, miraculously, is able to defeat the robot with the partial use of his staff!!
In Monkey Brains, Splinter becomes quite fascinated in April when he realizes that she has an innate ability to sense internal feelings (something that he was never able to learn properly). As a response, Splinter wants to teach her to become a Kunoichi (a female ninja).
In Panic In the Sewers, Splinter becomes pulled between allowing the Turtles to go up to the surface to find a source of information or having them stay in their home when their secret lair suddenly is put at risk of being destroyed by The Shredder's clan.
In Mousers Attack!, Splinter warns the Turtles that April O'Neil's missing cell-phone is not a major concern compared to the imminent threats of Baxter Stockman's Mousers and The Foot Clan. At the end of the day, the Turtles learn that, by choosing their battles poorly, they end up creating their own crisis...
In I, Monster, Splinter falls under the control of the evil Rat King, but he is eventually able to snap out of his trance (with the help of his sons) and he then defeats The Rat King with nothing but two fingers...
In New Girl in Town, Splinter explains to Leonardo that leadership is not about the repercussions of having the burden of being leader - It's about carrying it no matter what....Meanwhile, Raph believes that being a leader is pretty easy, but he is quickly proven wrong when he is put through the same stress that Leo is every single day.
In Baxter's Gambit, Splinter assists April in finding a suitable weapon that she can use. At first, she cannot use any of the weapons with ease - until Splinter offers her a tessen that he once intended to give to his daughter. This likely indicates that Splinter now views April as his closest daughter-figure.
In Karai's Vendetta, Splinter teaches the turtles and April that they can use just about anything to defend themselves if the situation calls. He uses Raph as an example, whom he licks in order to get him off. Meanwhile, The Shredder sends Karai to capture April in order to lure out the turtles, but April is able to apply her Ninjutsu knowledge to flee the situation. Back in the lair, the turtles congratulate April. Splinter, however, is skeptical, and he tells April that she still may be unsafe, due to the simultaneous threats that both The Shredder and The Kraang pose, advising that April should not leave the lair for a while... April, rather reluctant to cope with the circumstances, is eager to get started on stopping the enemies.
In Pulverizer Returns!, Splinter realizes that the Turtles have been growning complacent using their signiature weapons, and that they will have to adapt to using varied weapons if the situation calls.
In Booyaka-Showdown, Part 1 and Part 2, While the Turtles are forced to confront the Kraang and rescue April, Shredder uses April's abduction to utterly trick Splinter into confronting him. Splinter goes to the shredder's lair to rescue her; fighting many foot soldiers and his two mutant henchmen Dogpound and Fishface who he easily takes out. He then discovers that April is a hologram being projected by a Mouser that he destroys with a Shuriken. He then hears the Shredder's laugh. He asks his foe what he did with April. the shredder then reveals that he only needed April as bait to lure him out and now that he has; he had no use of her so he handed her over to his new allies, the Kraang. His arch-enemy then appears before him. Although initially amused at the discovery of Hamato Yoshi being a Mutant rat, Shredder quickly engages him in battle, angrily proclaiming that Hamato stole everything from him, while Splinter counters that Tang Shen was never, ever Shredder's. Initially evenly matched, Splinter begins to gain an advantage when he starts to rely on his abilities as a rat, partially breaking one of Shredder's blades in his teeth and running on all fours to evade his attacks, but Splinter is then knocked off-balance emotionally when he realizes that Karai is his own daughter, Miwa, raised to hate him and believe that he was responsible for the death of her mother. Unwilling to fight his daughter, Splinter finally decides to retreat, declining to tell his sons what he has discovered in favor of allowing them to celebrate their supposed victory over the Kraang.
In The Lonely Mutation Of Baxter Stockman When Donatello perfects the retro-mutagen he has been working on to cure Kirby O'Neil, he initially creates enough for two doses- one for Kirby and one for Splinter- but when one dose is destroyed before it can be used, Splinter assures Donatello that he is content to exist in his mutated form.
In The Wrath of Tiger Claw Karai becomes unsure of who to believe and feigns a defection to the Turtles' side while planning an attack on the lair with Tiger Claw. Splinter shows Karai a completed copy of the photo she carries around with her of her mother (the completed image being of both Yoshi and Shen), and makes her believe him finally.
In Plan 10
In Vengeance is Mine Splinter is once more reunited with Karai after the Turtles' successful rescue attempt. However, he makes the mistake of confiding the entire story of how her mother died to Karai, prompting her to return to Shredder's stronghold to exact vengeance. This results in her again being captured and used as bait to lure the Turtles into a vat of mutagen tainted with serpent DNA. In the course of the rescue attempt, Leo tries to free Karai (suspended over the vat), but Shredder's swipe of his gauntlet meant for Leo cuts the chain instead. Both Shredder and Splinter watch in horror as Karai is mutated into a serpent creature with snakes for hands. Again, Shredder blames his own mistake on Spliter, and Splinter barely manages to get through to his daughter before she escapes the fire that her struggle starts in the lab. Leo tries to apologize to Splinter for allowing Karai to escape the lair, but Splinter is too overcome with grief to acknowledge it.
In A Chinatown Ghost Story Splinter is seen meditating for days. Leo believes he is "healing his spirit".
In The Invasion, Part 2 Splinter fights Shredder and witnesses him seemingly kill Leatherhead. Splinter and Shredder's fight continues through the sewers even when the Turtles arrive. Splinter is then dumped into a sewage disposal similar to where Mikey trapped the Squirrelanoids. Later on, Karai saves him from drowning and brings him to dry land, nudging him before leaving.
In Vision Quest, Splinter appears to the turtles in a spiritual form, telling them while he is still alive, his spirit is detached from his living body. He instructs them to go alone to fight their spiritual enemies, and to forge new armour and weapons. After this, he tells them to sleep and vanishes.
In Return to New York, the turtles find out that due to the injuries he got from his battle with Shredder, Splinter is suffering amnesia, and thinks that he is just an ordinary rat. This leads to him being captured by the Foot Clan and held hostage by Stockman-Fly who was ordered by Shredder to find a way to restore Splinter's mind. April used her telepathy to bring him back to sanity. Hamato Yoshi then defeats the Shredder Mutants and then retreats with the Turtles, April, and Casey when the rest of the Foot Clan arrives.
In Serpent Hunt
Powers and Abilities
Splinter seems to be very adept in regards to the mind. For instance, when the Rat King attempted to hypnotize him, Splinter was able to defend himself from Rat King in his own dreams. Splinter has perhaps trained in the ways of ninja for all of his life, which makes him very methodical in physical situations, and able to act easily in difficult situations that require thought. Even though his mental fight with Rat King was rather strenuous, he still easily defeated Rat King with his sons' help, showing that he had to combine his thoughts with his physical power, which ultimately led him to nearly kill The Rat King....Splinter's feelings for his former family; His daughter, Miwa, who was taken away from him by his arch-nemesis, and his deceased wife Tang Shen, who was killed in a battle, and his determination to hold onto his current bond with the Turtles...is ultimately what gives him the majority of the abilities he has today. He can also seemingly read his foes' thoughts and predict their next move, implying that he can sense the projections of opponents (and use his keen hearing). This seemed to be evident during his fight with Shredder, during which Splinter also demonstrated his ingenuity by using his natural abilities as a mutant rat in the fight (something that he had never shown before, as he focused on training the turtles in more human skills), such as catching Shredder's blade in his teeth and running on all fours. Despite The Shredder taunting Splinter about his daughter, Splinter nearly defeated him, until Karai ultimately made her interference. When April O'Neil's psychic powers first became evident in her ability to sense Dr. Tyler Rockwell, Splinter revealed to her that he has similar abilities, but had to hone them over a long time through training and practice; this sets him apart from April and the Kraang (who are already natural-born psychics to begin with) and Dr. Rockwell and Dr. Victor Falco (who were augmented with psychic powers).
Leonardo - The eldest of Splinter's four adopted sons and the leader of his 3 younger brothers. Splinter seems to share most of his knowledge with him. However, it is just in hopes of embracing Leo's role as the leader - and making him more tactful and intelligent. Because of Leo's status, Splinter always discusses how to perfect his leadership...
Raphael - The second oldest of Splinter's four adopted sons and the most aggressive of his brothers. Him and Splinter are shown to have similarities in their temperament, such as when Splinter retaliated on The Shredder, which resulted in the tragic death of his own wife. And much later, when an arrogant man caught the turtles on video with an I-Phone, Raph sought to break the phone 'and the man's face'. However, due to the knowledge that Splinter had acquired from the result of his temper against Shredder, he tells Raph that he must maintain his temper...in order to get the best of the situation.
Donatello - The second youngest of Splinter's four adopted sons and the most technological of his brothers. Like he does with his other sons, he occasionally enjoys teasing Donnie and teaching him important lessons. At one point, he attempted to teach Donnie a lesson in not forcing someone, e.i. April, to like another person, e.i. Donnie, back.
Michelangelo - The youngest of Splinter's four adopted sons and the wildest of his brothers. Splinter says that Michelangelo can fight easily without thinking. Despite Mikey's dimwittedness, Splinter claims that he actually shows great potential.
Karai / Miwa - Splinter's initially supposedly dead daughter, Miwa, who was taken away by Oroku Saki after the events of their final battle and raised as his own daughter. Splinter only found this out upon being forced to duel with the Shredder, after April O'Neil's abduction by him. Once he knew the truth and after she showed up, he refused to fight her, leaving her and his own enemy alive. Even though Miwa is out of Splinter's life in one sense, Splinter still has one place that he still holds her—his heart. Despite Karai's place as a foot assassin, Splinter still deeply loves her and believes that there is still good in her. He also had no hesitation about trying to save her when she fell of the roof. When Karai learned the truth about Splinter being her true father, she was rescued by the turtles and they brought her to the lair where she hugged Splinter. Splinter was deeply devastated when Karai was turned into a mutant serpent. However, Karai recognized her father before escaping. Near the end of "The Invasion, Part 2", mutant Karai saved Splinter from drowning in the sewers. It was shown in Serpent Hunt that he wished to be reunited with his daughter.
Tang Shen - Hamato Yoshi's wife, who died a long time ago. Not much is known about their relationship, but it's implied that they both loved each other deeply. Even though the Shredder's jealousy was the reason for Tang Shen's death, Splinter blames himself for giving into the Shredder's presumptuous anger and initiating the two's bitter rivalry.
Oroku Saki - Found by Splinter's father when the Hamato Clan wiped out the Foot Clan, Shredder was raised as Yoshi's brother until he learned the truth about his past and their brother rivalry got bigger proportions.
April O'Neil - A teenage girl who met Splinter and the turtles after being kidnapped by The Kraang. Since he lost his true daughter many years ago, he has comes to view April as his surrogate daughter, and he even supplied her with the weapon that he once intended to give to Miwa. As of Return to New York, Splinter considers April to be part of his family.
Casey Jones - Splinter respects Casey as an ally and also as a friend to both April and Raphael. Since being introduced to Splinter and the turtles, Casey became a regular visitor to the lair. As of Return to New York, Splinter considers Casey to be part of his family.
Slash - Before Spike's mutation into Slash, Splinter was barely ever seen acknowledging his existence, and was only shown using him as a sounding board to tease Raphael into listening to Splinter's story in Turtle Temper. But after Raph and Slash became alienated in Slash and Destroy, Splinter recognized how deeply Raph had loved Slash, and counseled Raph in dealing with his grief. Since Clash of the Mutanimals, Splinter and Slash have themselves been shown to be friends and allies. When Slash was being mind-controlled by the Shredder, Slash brutally attacked Splinter, severely wounding him. When Slash was freed from the Shredder's control, Slash begged for Splinter's forgiveness, only for Splinter to consider Slash blameless for the incident. Still, Slash's attack took its toll, with Splinter still in physical therapy during The Deadly Venom.
Leatherhead - In It Came From The Depths, Splinter was the second person after Michelangelo to sense that Leatherhead had a good heart, and encouraged his sons to show Leatherhead compassion. But when Leatherhead suffered a bout of uncontrollable rage, Splinter angrily kicked him out of the lair. This did not become an enmity, as the two met as good friends in Battle for New York, Part 2 and fought the Shredder together. Leatherhead's then-defeat enraged Splinter, reigniting his determination to defeat the Shredder.
Kirby O'Neil - Splinter has always regarded April's father positively, though they have seldom been shown interacting with each other. Their most meaningful interaction was during The Deadly Venom, when Kirby frantically brought April to the lair after Karai envenomated her. When Donatello proved powerless to heal April with medicine, Splinter remained with April and Kirby and used an ancient poison-draining mantra. Kirby and Splinter briefly argued over the wisdom of not taking April to a hospital, but Splinter successfully healed April and earned Kirby's gratitude and esteem.
Timothy / The Pulverizer / Mutagen Man - Timothy was neither clearly Splinter's ally nor his enemy. Splinter's biggest impression of Timothy was that he is a doofus, and that it was inappropriate for Donatello to teach Timothy their ninja arts.
Oroku Saki / Shredder - Splinter's old step-brother and current arch-nemesis. They fought over Tang Shen when Saki was consumed with jealousy, which resulted in Splinter's house catching ablaze and collapsing on Shen, killing her. Up until this day, Splinter has vividly remembered that moment. Unbeknownst to Splinter, Shredder stole his daughter, Miwa, during the night of the tribulation and raised her as his own daughter. He began teaching her in the ways of the ninja, and he later convinced her that Splinter was responsible for her mother's death (which is, of course, not true). Recently, Shredder has organized an army of ninja called the Foot Clan, whom he deploys to locate Splinter and his disciples after learning of the latters' whereabouts (New York City). Eventually, Splinter and Saki duel once more, during which Splinter discovers the truth—that Karai is his own daughter, raised to hate him and the turtles. This both infuriates and depresses Splinter...when discovering that his daughter has been dealt with in the wrong hands.
Chris Bradford / Dogpound / Rahzar - Splinter has only battled with him once upon confronting the Shredder. Splinter seems to be relatively more skilled in combat than Bradford.
Xever Montes / Fishface - Splinter has only battled with him once upon confronting the Shredder. Splinter seems to be relatively more skilled in combat than Xever.
Dr. Victor Falco / The Rat King - Has attempted to (and succeeded at) taking over Splinter's mind, while under the alias of the "The Rat King" by using deceptive tactics based upon their similarities.
Irma / Kraang Subprime - When Kraang Subprime assaulted the lair in The Invasion, Part 1, it was Splinter who defeated him. Kraang Subprime survived the encounter though, reappearing in Battle for New York, Part 1.
- Splinter: "Raphael, there is no monster more dangerous than a lack of compassion." (sees Leatherhead) "My mistake..." -It Came From the Depths
- Splinter: (To Leatherhead) "STOP! Get away from my sons!"
- Splinter: "Of course. I am compassionate, not insane." -It Came From The Depths
- Splinter: "That's the choice I made. What choice will you make?" -Turtle Temper
- Splinter: "I hope you have learned, turtles, that truth is not the only thing that hurts!" -I Think His Name is Baxter Stockman
- Splinter: "The first rule of being a ninja is do no harm. Unless you need to do harm, then do lots of harm!" -I Think His Name is Baxter Stockman
- Splinter: "You were all very lucky. (Raphael responds) Few have ever faced the Shredder and survived. (dialogue) Perhaps. But that no longer matters. It is clear now that the Shredder is a problem that will not go away. So prepare yourselves, my sons... because as of this moment... we are at war." -The Gauntlet
- Splinter: "Yes, because you will stay down here until you are ready! No patrol, no games, no rest! There is only training, starting now!" -Panic in the Sewers
- Splinter: "If I were the Shredder, none of you would be breathing right now! Understand!?" -Panic in the Sewers
- Splinter: "No, I am a man! I am Hamato Yoshi!" -I, Monster
- Splinter: "My place... is with my sons!" -I, Monster
- Splinter: "Oh, the Olympics?" -TCRI
- Splinter: "You fool...! Do you have ANY idea what you've done!?"
- Splinter: "Look closely at this face, Shredder. For it is the last thing you will ever see!"
- Splinter: "You took everything that I loved. Everything! And still you hunt me down! So... I fight you now... to end this!"
- Splinter: "You never had anything but your hatred! And if you defeat me, you will have NOTHING!"
- Splinter: "... Miwa?"
- Splinter: "My son, for someone so intelligent, the obvious often eludes you."
- Splinter: "I lost many things: my family, my home, my name. But I gained many things as well like the four of you."
- Splinter: "You're too busy trying to be this unrealistic television captain. Instead you should listen to your mind and heart. Only when you listen to yourself and your brothers will you become the great leader you are destined to be.
- Splinter: "The fist of youre have the power of the mightiest of earthquakes. They can bring the strongest of men to their knees.
- Splinter: "Anger is self destructive. Let the emotion of anger wash over you like a river over an immovable stone." -Turtle Temper
- Splinter: "Yes... and no. Karai may have failed her mission but if the Shredder wants you that badly, I doubt he will stop until he has found you and with the Kraang after you as well, I hardly doubt it is safe for you on the surface so it is probably best that you stay down here with us."-Karai's Vendetta
- Splinter: "April will come back to us on her own time"
- Splinter: "You run like a coward when you're not in control!"
- Splinter: "Rage is a fuel that burns quickly!"- The Invasion, Part 2
- Splinter's given name, "Yoshi", (喜), translates as "like, love, enjoy", or "joyful thing". Splinter's surname "Hamato" (濱戸), translates as "beach/sea coast/river bank door/family". If written purely in hiragana, "Hamato Yoshi", (はまとよし), means "Alright still".
- This is the third version of Hamato Yoshi being mutated into a rat, the first version being from the 1987 series and the second version being from the Archie Comics series loosely based on the 1987 series.
- Splinter's completely avoids contractions in his speech. Instead of "doesn't", "won't", "he'll", "I've", etc., he says "does not", "will not", "he will", "I have", etc.
- Splinter's bed is a bare tatami, a kind of traditional Japanese movable flooring mat. It is normally customary to sleep on a futon on a mat, rather than directly on the mat itself, which has a harder surface. In I, Monster, Splinter is shown sleeping on it in his bedroom, but is also shown sleeping on it in other rooms like the dōjō and the common area.
- In , Splinter found out that his daughter, Hamato Miwa, is still alive.
- In the trailer for the season two finale The Invasion, Part 1 and Part 2 Splinter says "No, you are making mistake" as he struggles while trying to fight Kraang Subprime off. However in the final product, he says nothing.