Now You're Just Showing Off (Season 1)

Millhouse Manastorm has nearly 50 million HP and four abilities. Interrupt his Frostbolt and Shadowbolt casts. When he summons Power Crystals, two totems spawn with 78k HP and fire sparks at Millhouse — standing in front of those sparks grants him stacks up to 100, each stack increasing his damage by 1,000%, so destroy the crystals before he accumulates too many stacks.

Epicus Maximus has the shortest enrage timer due to an RP sequence at the start, requiring around 95k DPS. As melee, dodge small void zones and the laser, then interrupt the AoE cast immediately after the laser ends. As ranged, pull the boss to one corner and move to the opposite corner when the laser begins to gain free DPS time while avoiding the AoE entirely.

Disruptron Mk. 3R-Alpha requires around 90k DPS. Before 35% health, it activates a random turret periodically; at 35% it activates all turrets simultaneously. It also performs a long cast that stuns everyone in melee range for 5 seconds, which can only be interrupted by CCing the boss itself.

Zen'shar is one of the required rare brawl bosses for this achievement. No additional ability data is available, but defeating it is required alongside the other three bosses to complete the achievement.