The Shapes

Defeat Donu and Deca, the paired Act 3 boss (see The Time Eater and The Crow). Donu gives the pair Strength, Deca gives them Block and Dexterity, alternating each turn - so focus one down rather than splitting your damage (Deca first usually, to stop the block wall). AoE is great here. Act 3 boss RNG decides the matchup. If you want the Ooh Donut! achievement, this is the fight to bring a Feed to.