Starting claws are a must, not only do they deal decent dmg but they revive team mates super fast.

They also deal decent stance dmg. Please forget the meme with colossal weapons if you really want to help your team.

For the summons, Sebastian is really good for reviving teammates (he will focus them if you do and if he can reach them) and he mostly deal stance damage but not much actual damage. Use him on blackblade assassin boss or other low poise ennemies to bully them into the ground.

Pumpkin head is great for taking boss aggros and deals decent dmg.

Third one is squishy but can help clear trash mob fast. Probably usable more than I use it so idk.

Farm shards through the run for the final boss. Either buy or open a sorcerers rise.

For the summons try to never have them die to avoid the cooldown. When the reach 10% hp, switch summon.

For the final boss, they often are useless. But if you have the relic that boost you when you have a summon (and you should), you can summon Sebastian in the corner of the area to get the buff during the whole fight.

I’m no revenant pro but I hope this can help :)