Some TMNT stuff was always meant for grownups.
A methodical and dedicated Time Lord, committed to keeping the time stream of Earth clean and unpolluted. He has trained several apprentices over the years and had found life with his latest apprentice, Renet, to be by far the most difficult. Prior to taking on Renet, Savanti Romero was his apprentice, who ultimately turned on him and tried to "edit" him out, forcing him and the 79th Level to banish him to 1406 A.D. He did, however, have high hopes for Renet, since he saw something of his own youthful rebellion in her.
Lord Simultaneous was originally born as a simple man on Earth in the Middle Ages. Marcus' own Time Lord tutor was Lord Marcellus Timagetus. Marcellus, who found and conquered the 79th Level from his origins in the Roman Republic (circa 180 B.C.), rescued the orphan Simultaneous from his home during a particularly violent siege during the Middle Ages and brought him to the 79th Dimension of the zero-time to be his student. Originally Marcellus found the young Simultaneous to be disobedient, rude, quite unruly, stubborn and far too bright for his own good, knowing talent when he saw it, he became a gifted Time Keeper and then eventually became Timagetus' successor. He spent some time experimenting with the creation of magic-manipulating micro-chips, hoping to develop ways of assembling power objects from digital/magical components (Transdimensional TMNT).
Simultaneous began to train students after his ascent, although two soon would get to be big trouble: For one was Savanti Romero, who wanted to be the master of time only to live out his lust for power, the other was the young Renet, as equally talented as rebellious as he once was, even in his youth, mixed with a good dose of clumsiness and a too great curiosity about everything.
Although Renet in her first misstep in which she met the Turtles for the first time and in a chain of events, Savanti Romero was freed from his exile in the Middle Ages, and was harshly punished, Renet managed over time, to become a true time guardian and possible successor.
In issue 8 of Teenage Mutant Ninja Turtles, Renet Tilley sneaks into Lord Simultaneous' personal chambers to steal his Sceptre of the Sands of Time so she could escape her 'boring' life. Against his wishes, Renet once time-traveled off with Lord Simultaneous’ Sceptre of the Sands of Time to modern-day New York. She teleported to New York in the year 1986. Simultaneous was angry, and followed her. He followed her throughout dimensions trying to regain his scepter. Fleeing Simultaneous further, she and the Turtles went to 1406, where they teamed with Cerebus to get the Sceptre back from Savanti Romero, who was bent on stealing it for himself. Simultaneous appeared and cast Savanti into prehistoric times (TMNT Vol. 1, #8).
The comics he has appeared in include but are not limited to:
- 1986 January 1 Teenage Mutant Ninja Turtles (Mirage Comics) issue 8
- 1989 January 1 Teenage Mutant Ninja Turtles Graphic Novel book 3 issue 3
- 1990 June 1 Teenage Mutant Ninja Turtles (Mirage Comics) issue 33 Turtles Take Time
- In the RPG -Appendix Transdimensional Teenage Mutant Ninja Turtles, Lord Simultaneous' age is given as 57. He has been at the office of master time since his first appearance until the last 16 years.