Annoying little thing really. The main difficulty of this fight by far is the terrain restricting your dodging options. Phase 1 and 3 are the hardest for me, the bombs can pin you down and make it very tough to avoid a fast fireball afterwards.
Phase 3 in particular can be very nasty if it uses the attack that shoots fireballs and bombs at the same time. If you're lucky you won't have to deal with that if it decides to only use the 4 bombs attack or summons minions instead.
Don't underestimate the minions, they have huge hitboxes and can swarm you if you're not careful. They also have very bizarre pathfinding, they primarily seem to try and hunt you down but can also waffle back and forth sometimes or take a sudden detour, throwing you off your rhythm.
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