I've been trying to create a fan-fictional story using characters from the Ninja Turtles with the storyline of Samurai Seven, and I would like some help with one of the characters.

The basic character breakdown is this:

The Leader: Leonardo

The Lancer: Raphael

The Big Guy:

The Smart Guy: Donatello

The Old Guy:

The Young Guy:

The Funny Guy: Michaelangelo

I plan on using Leatherhead fod the big guy, and Mondo Gecko for the young guy,although Mondo could easily swap with Mikey for either role.

Now, I'm looking for the old guy, not necessarily ancient, but older than the other six. I know that Splinter would be the obvious choice, and I was originally planning on using him; however, I have since decided on using a reptilian character since the other six characters were also reptiles.

So, that being said, which character from any Ninja Turtle comic/cartoon/movie/TV series should be the old guy, it doesn't necessarily have to be a friend, it could be a foe with whom thet share a common goal/enemy (at least, as far as the storylines go. I know they have a character or two who is a komodo dragon, but I don't know too much about them. I've even thought about using the Savage Dragon since they've already teamed up a few times, but I'd rather it be someone from the same company. Any thoughts?

Truthfully I think by requiring your last character to be reptilian you are going to limit yourself in both the possibilities for characters as well as their role in your story. I would absolutely have used Splinter as they old guy character, he plays such a big role in the lives of the turtles and the world they exist in it only makes sense to utilize him for your story. Plus I can't really think of an "old" reptilian character in the Turtles stories that isn't Leatherhead.

I assume you are writing this based on the cartoon Samurai 7. However have you ever seen the original Seven Samurai from Akira Kurosawa? It is definitely worth watching if you haven't, especially because that movie is what Samurai 7 is based on.