I wanted to do one of these line-ups as well. You can notice the different shapes of snouts and eyes I draw to distinct the turtles. (Donatello looks like a fish, damn.)
So why did any version of Splinter take the turtles in? Compassion? Parental feelings? He thought they might make good bodyguards in the future? Was he bored?
No. In the original Mirage series, and I find this fascinating, he took them in because he wanted to train them as assasins who would kill Saki one day
. This Splinter's motive was to raise tools for his revenge.
It's awesome. Virtuous Leonardo, gentle Donatello, hot-headed Raphael, happy Michelangelo - all of them were brought up to kill a person.
And one wonders what exactly the point of their existence, the goal of their lives is.
Teenage Mutant Ninja Turtles © Kevin Eastman & Peter Laird