So I have been playing this character for a couple of months, and truth be told its just not working for me. He's playing his role in the group fine and has plenty to do, but the character turns out to be hard to motivate and the motivations he has are starting to run perpendicular to the rest of the group.
Short of going kamikaze and getting a new character that way, what would be the right way to go about getting this character replaced?
Make sure your GM knows you wish to change course. After that, it depends on whether or not you don't like just your character's personality or the entire build as well.
One of the hardest things to reconcile between in-character and out-of-character is the retirement or addition of a new PC. Why is there a new guy? Where did the old one go, and who gets his equipment? How come they are suspiciously similar in skill?
Take the Leadership feat, and introduce your cohort as a protege that has sought out your character to train under them. After a little while, retire your old character, and play the cohort as a full PC.
If the build is fine, but the roleplaying is starting to get stale, there are a few ways to shake things up without completely switching characters.
Maybe you're fine with your character...in character. But a powerful intelligent item uses its high Ego score to get the character to act in its own interests. Or the character is possessed by a Fiend of Possession, gaining some power in exchange for doing a demon's bidding.
First, talk to your GM and make sure they know you want to replace the character. Most will be fine with this, but you want them to be prepared to help you, and you should also be in agreement about how you'll introduce the new character, what level they'll start at, etc.
Once all that is taken care of, it sounds like you have an unusually convenient option for this. In your own words:
the character turns out to be hard to motivate and the motivations he has are starting to run perpendicular to the rest of the group.
That being the case, you, your GM, and the other players should be able to engineer a scene (as dramatic or matter-of-fact as you wish) where your character realizes they're not really fighting for the same things as the rest of the party, and takes a different path.
Alternatively, you could talk to the GM about altering your character's motivations. Does he meet someone new who makes a big impression? Lose someone important to him? Have a religious experience? All these can dramatically change someone's motivations and actions (though not usually their whole personality). If you otherwise like your character and their abilities, this may be the way to go.
