I need help with a unique spin on the whole "possession" concept...

[Dragonmaster_Dyne]

I'm debating on an idea for a villain who unlike the usual God of Death, Destruction, etc. isn't possessing a willing host, but the host and the spirit of the deity literally become one body. The two characters willingly became an entirely new being altogether. The general idea I had is the ancient war that nearly destroyed the Old World in my fantasy was caused by the corruption from the old god(dess). In summary, the deity's original body was destroyed so all that was left was its spirit who merged with another character who fell into the same level of despair post conflict.

Now the question I have is should I have past memories of the two characters always at odds or simply since it's a new character start forming a new life in the collective goal of returning the world to nothing? This character would fall under the "Ultimate Evil" villain subcategory.

It's just a random idea I had the other day.

 

[Darkfantasy]

I would do both. Maybe begin with the conflict between memories but then slowly have them merging to become one new life, like a transformation period. But it;s not really a form of possession since it's the state of being controlled by an evil spirit. But if the character is willing, the demon has no need to control them

 

[C. R. Rowenson]

I like Darkfantasy 's idea. This could create a compelling struggle as the person becomes more and more villainous and also give the heroes time to react and make plans before the Ultimate Evil unlocks all of their powers.