Barrier Knights. One in the first room, one in the hallway after the first room, and one in the boss room. The second one can run to the next room; recommended to kill it quickly before it does.
Unstoppable Ogre in the second room.
Solar Wizard in the first room.
Fire Pit – When defeated, Acolytes spawn fire pools that cause damage over time.
Two Hive Guardians: one in the first room, and another in the second.