How to build a character of god-like aspirations?

[SangoProduction]

I had a somewhat simple concept, inspired by a video (https://www.youtube.com/watch?v=gyGrsv9uOA0): A sea captain that "fell into" the astral plane by a natural portal. He spent "years" traveling the plane to return to his crew and family, using his magical gifts to guide him. The way the plane channeled magic was special. It formed a cruel... addiction.
When at last a portal back to the material plane was found, it took untold "days" and will power just to walk through. It was one way. Everyone from his old life had moved on. But the addiction was still there. A withering pang of "hunger" that is only sated for vanishing moments by casting magic.
With nothing else tying him to the world, he decided he should attempt to transcend it. Become a being of the astral itself. A god. A caretaker of any such mortal trapped in such an existence as him.


The Mana sphere and the Addictive Casting drawbacks are obvious pickups.

But am honestly not too sure what else to do with this character.

[Doctor Despair]

Does Ur Priest exist in this system?

[SangoProduction]

Does Ur Priest exist in this system?

It could pretty well be adapted into Pathfinder.

[Xei_Win_Toh]

Astral bloodline sorcerer?
Mythic ranks?

[icefractal]

On the one hand, Addictive Power is obviously useful, and being buffed up as close to 24/7 as possible is thematically well-suited.

On the other hand, this means he has a lot less need to "feed the addiction" by casting, so it depends on how important a factor you want that to be. Although you could still say it's enjoyable and he'll do it as often as possible.

Speaking of drawback feats, Habit Forming is another well-suited one.

If it's allowed, Manathief is a good fit, slurp up all the SP available so you can cast more often. Of course that relies on caster foes being non-rare, and ideally defeating them nonlethally so that they can be drained fully after combat. Manathief+Flow is also a good way to shift SP around within the party as needed, but that doesn't feel as fitting.

Because of the Astral connection, Warp as a second focus would fit.

Not sure how much "becoming a god" is something you want to do on-screen rather than just being a motivation, and how much it'd be rules-driven or not, but the most key Spheres abilities for High-Magic Nonsense™ are (IMO) Create Demiplane and Give Magic Life. With those in play, you can do some very impressive stuff.