@stallmandibuzz-reserving Oshawott as your starter since I haven't been on in god knows how long. I will update before i must leave free wifi access
Take Samurai the Oshawott. This Oshawott is a great fighter, but does not like fighting nor killing. So, it must not deal the finishing blow to a pokemon that was weakened below half health or has a status effect it did not inflict. In addition, it must learn at least 2 moves involving slicing (razor shell and swords dance are ok).
The most important part, however, revolves around his honor. He believes in defense more than offense, so much that whenever a teammate is about to take a lethal blow, he must switch in and take the hit for them, whether or not it would kill him. You may want to overlevel him or invest in bulk so he doesn't die early.