Sholomance Acolytes are melee casters, their spells are not very powerful, but their melee deals 300-450 damage to casters, so its very important for a caster not to aggro them.
They cast the following spells:
Shadowform
Mana Burn
Cripple, reduces attack speed by 50%, reduces movement by 50%, and reduced Strength by 50%, lasts 15secs.
Dark Mending, works just like a normal heal.
Passive: Mind Flay
Strategy
There isn't anything special about this fight, but their Mind Flay is very potent and always dispel Cripple if its on the tank.