Larian Studios Forums Divinity - Original Sin Divinity - Original Sin - Enhanced Edition Damage calculation for Attack and Spell

ok i understand Str and DEx and Int don't actually increase your damage

so i am wonder what does increase your damage for Attacks and Spells, i know level and damage reduction has a relation with level, but what if you ignore all reduction and just see what stuff add to damage.

Also what is the modifier for enemy saving throw difficult?