If Byleth sides with Edelgard, they awake to discover that Rhea has taken sanctuary in the Kingdom capital of Fhirdiad and that Adrestia is locked in a stalemate with Faerghus and Leicester. In a last struggle, the Resistance defeats Rhea. She, on the other hand, suffers from a draconic degeneration-induced mental collapse, turns into a giant dragon, and goes on the rampage. Rhea confesses that she is one of the goddess's children, and that Byleth is the culmination of her millennia-long efforts to bring her mother Sothis back to life. The Resistance attacks their castle, Shambhala, an underground metropolis, and kills their commander Thales. After that, Edelgard's vassal Hubert informs them, posthumously, of the cult known as 'those who slither in the dark,' which is responsible for the destruction of Fort Merceus and much of the tragedy that has befallen Fódlan. The Resistance storms Enbarr, kills Edelgard, and rescues Rhea. However, the fort is destroyed by ballistic missiles that the Resistance refers to as 'javelins of light'. Byleth continues the assault on Adrestia, and conquers Fort Merceus. Imperial forces kill Dimitri and drive Claude into hiding at Gronder Field. The Resistance launches an attack on Adrestia after receiving reinforcements from Lady Judith of Daphnel. The two establish a Resistance army and pledge to overthrow the Empire after reuniting with Rhea's second-in-command Seteth and the former Black Eagles. If Byleth joins the Church, they will wake up to find Rhea has vanished.

Panzer corps reform units