Larian Studios Forums Divinity - Original Sin Divinity - Original Sin - General Tenebrium

From what I have read in the forums, and from my experience ingame, this is how it works:

1. Tenebrium +1 allows a character to use tenebrium without getting the rot.
2. Tenebrium weapons are unaffected by weapon skills (damage boost) other than tenebrium skill.

I think, that this is not the best way to handle it for obvious reasons.

Another way to handle it that comes to my mind is that at certain point of the game, in order to allow the party members to handle tenebrium, they should get immunity to rot.