The Underworld Incarnate

Battle A: Lyrah's Cocoon phase heals on every hit received, so use only high-damage attacks against it. Battle B: an upper-right enemy group holds/defends; avoid alerting the centre group.

Boss: Lyrah

Battle A: let enemies approach, use weak attacks to destroy her corner shields first, then commit heavy hitters. Her Cocoon phase heals on every hit received, so use only high-damage attacks against it; Battle B: send the Hero and strongest units west toward the exit while an upper-right group holds/defends; avoid alerting the centre enemy group by not engaging their battalions