[@Hael]

*cringes at how much is being forcibly spoiled by this conversation*

For very good reasons, neither the Darkness domain nor the brother idea are ideal for said demigod.

If you can help me think of a domain that would include such things as (Treachery) and (Power) as in the rulership sort of power, that would actually be an acceptable alternative to the Evil domain for me.

I know exactly what the guy's powers and general traits will be like, but I made the mistake of deciding upon such traits prior to inventing a Domain and Portfolio. So now instead of building personality around powers I have the considerably harder reversal of that situation.