Aukuras in R9 has an attribute which converts Aukuras into a totem which grants fire elemental damage. It is quite good, at level 10 you get nearing 1k fire elemental damage to all your hits with around 330 int.
Divine Stigma, besides the STR/INT buff, also boost zaibas’s damage by around 50%. Stormcalling increase lightning damage by 2.x ish . Note that these 2 damage buffs are additive, they don’t stack after one another.
With lycan’s damage boost, Damage dealt by Zaibas with all these combined isn’t weak.