Donu and Deca are a duo fight. Donu buffs its Strength and Deca applies Block. The key is to deal damage to both simultaneously or focus one down quickly. If you kill one, the other will gain a significant buff. Ideally, you want to bring both down to low HP, then finish them off in the same turn or consecutive turns. AoE damage is extremely valuable here. Be prepared for high damage and consistent block from Deca.
