Kuldjargh

Recommended strategy
They can overwhelm your group if not properly controlled.

Send one person, usually someone with ranged attacks/spells and fast movement, to get their aggro and run around with them. This kiter should keep them away from the party, near the border if possible (sometimes the Kuldjargh fall off the platform and can't get up again; use this to your advantage). They have so much HP that beating them down could take time.

If your party chooses to kite them, make sure that only the kiter (and no one else) is hitting them.