Usually magic users that use healing or wounding spells.
Alexander fought a Ravenlos Cleric guarding the foot of the Manannan's mountain retreat for Ravenlos in King's Quest ZZT. It was mentioned in King's Quest ZZT 2, that Castle Daventry has a Cleric for healing the wounded in the castle.
Another Cleric was part of rebels that were fighting against the Dalban and Relentless Army in King's Quest ZZT 2.