Let's say he is like 24 or 25 years old. What should be a job for him, if you think he should have some sort of an occupation.

I don't think it would hurt to make both his parents paleontologists.
their fields could be how they met.

also, you can never go wrong with a deliveryman or a courier.
it'd allow him to already have a bike.

I really like that idea. We'll develop it more after we agree on a name for him.

My issue is that I really like the name Rex, but it makes him sound almost like a cheesy action hero or cartoon character (which is suppose isn't too far off :o) if it were his real name. That's why I'd prefer it to be a nickname that he goes by almost exclusively to strangers.

Now he could have an american first name, but then you'd have to pull at straws coming up with a reason he'd go by a nickname so often. Growing up in America with a foreign name gives believable reason for him to prefer something like Rex.

I like the idea of calling him rex but can't find a good reason to justify it so far.

Although I mainly prefer because of the puns, the punny the better.

I'll make Rex his nickname. What should we make his actual name then? We're deciding between Ray or Henry.

I like the idea of Ray as was previously mentioned in this thread ray can also be close to Rei so it works like that way.

Ray "Rex" Kaseki. Ray starts with an 'R' to boot, further realizing the nickname. It's growing on me. I like it.

By the way, I've had a bit of free time to think about background and story info. Both of which tie really well into the origin of the villains. I think it's a pretty solid idea, but I'll explain it extensively once we get there.

Kamen Rider Paleo - Ray "Rex" Kaseki
Occupation: Delivery Man
We have his name, so let's come up with a story for him. We know he's a delivery guy and he is half American and half Japanese. His parents are paleontologists.

Okay. So. I've realized my basic backstory for the character also sort of relies on a plot involving his parents, the villains, and the origin of the Driver.

Urg. I don't want to come across like I'm trying to take too much control here, but I really think the three work themselves into each other really well. Let me condense my thoughts and pitch all three together once I've come to a conclusion.

Good writing usually doesn't follow an order of operations or finite steps in its creation. In my experience, it usually starts with a solid overarching idea and works from there.