Okay so i managed to kill spider 20 on manual(black knight as the tank, spirit host as the attack buff and cleanser, ultimate galek as the burn, apothecary as the speed boost and heal plus the def aura, and scyl as the secondary heal, stun, turn meter reduction and revive) 

black knight initially tanks the spiderlings but for some reason after the spirit host casts the cleanse, the spiderlings attack her, ignoring the affinity. idk what to do

Edit: I just speed tuned it a bit and its fine now. I just need it so spirit host is just even 1 speed faster than black knight. Now I just need to change his masteries to have more resistance then I think its almost 90% auto win. spirit host and ult galek is still lvl 50 since energy problems lol