The backstory of Savanti Romero in his 2003 cartoon incarnation closely parallels with his Mirage comic book template. The main differences are he's never been married, and the Turtles and Renet confront him only twice.
Savanti Romero was once an apprentice of Lord Simultaneous but once desired to have the Time Scepter. However, Simultaneous defeated him, transformed him into a demon-like state and banished him to 1406 A.D.
Savanti desired revenge and eventually managed to cast a spell to draw the Time Scepter to him, which brought Renet, another of Simultaneous' apprentices who tried to borrow the Scepter to have some fun, and the Turtles were pulled in with her. Savanti used a spell to create earth warriors to take the scepter for himself, but it was not strong enough, as when the warriors were defeated, they were reclaimed by the earth, forcing Savanti to capture Renet. With the power of time on his side, he felt he had nothing to fear. But the Turtles knocked it out of his hands as his pet dragon, soon evolves into Ultimate Drako, and grabbed it. Renet summoned Simultaneous, who banishes Savanti to the Cretaceous era.
Savanti made a new plan for revenge and managed to make a small army of dinosaurs. Using a spell, he used a number of dinosaur bones in the present to contact the Turtles, challenging them to meet him at "The Ring of Fire", which was back in the past. Renet, with permission from Simultaneous, brings the Turtles to the Cretaceous era.
Savanti captured Renet and brought her to a structure of bones. He revealed to everyone his plan to use his magic to make a lightning bolt to strike Renet, which would ignite a number of volcanoes, pushing the Earth to avoid the meteor that would wipe out the dinosaurs. In doing so, he would not only be more powerful than Simultaneous, he would also ensure that the Turtles would never exist without the existence of humans. Savanti made an armor of dinosaur bones but got struck by his own lightning bolt and tumbled into the lake below. After his second defeat, Romero no longer appears in the series