Overview
Nerissa's Invasion of Xalmyrra is the strike on Erenmyr's coast after Gabriel pushes Theryssa and Thiravos into Raphael's plan to attack Xalmyrra. Nerissa, Nero, Kalyx, Brontes, Lucilla, and an island-nation skyship fleet attack the coast; Brynor, Orin, Tazarin, Seralyth, Feryon, Celia, and allied reinforcements defend it. The Erenmyr strike ends with Lucilla unmaking Nerissa, Nero losing the force of the wave shard, and Brynor containing an essence bomb underground and disappearing.
Causes
Alistair's hidden sabotage at Zarephon destroys the mountain during the attempted source closure and traps Eira, Kaelion, and Xarion beyond the breach. Nero survives and returns to Pelagia. Because Nero guards the cave entrance and Nerissa withdraws from the God Realm to protect him, Pelagia can blame them for the mountain's destruction. The Pelagia Consulate debates neutrality, the Order, and Raphael. Gabriel intervenes in Pelagia, threatens the city with unnatural cold, and offers protection in exchange for Theryssa and Thiravos joining Gabriel's planned attack on Xalmyrra and sharing gate knowledge.
Nerissa accepts after demanding that Garrik be spared. She intends the alliance as a temporary bargain that buys time for Lucilla to master unmaking. Lucilla rejects the decision. Kalyx begins mobilizing Pelagos and Thiravos, and the island nations prepare a skyship fleet.
Fleet Movement
The fleet leaves Pelagia, gathers Pelagos ships and mages into the island-nation skyship fleet, and follows Gabriel's direction toward Erenmyr's coast. Gabriel gives Nerissa a stormcloud crystal for a lightning mage, later used by Kalyx. Nerissa orders a quick subjugation with as few deaths as possible. She also prepares Nero and the ocean for the strike on Erenmyr's coast.
Xalmyrra positions windweavers, airships, and mages along the Erenmyr coast. Brynor, Orin, Tazarin, Seralyth, Mirael, Feryon, Xandor, Celia, and Thalcoris reinforcements gather before the invading fleet reaches land. Nero approaches first and asks for surrender. Brynor and Orin refuse, and Orin incapacitates Nero with a touch. Nerissa retrieves Nero; she chose Raphael's side because Raphael and the Order would otherwise threaten her people.
Erenmyr Coast
Orin's resonance attack destroys the nearest skyship and damages the fleet. Gabriel descends with a snowstorm. Nerissa and Nero raise a massive tsunami. Tazarin shields much of Xalmyrra's force with a starfield barrier, and the defenders fight skyships, foreign mages, divine attacks, and wave magic across the coast.
Lucilla fights from the invading side and avoids kills. She knocks Xalmyrran mages unconscious, heals them subtly, and places herself in the skyships' firing lanes. Seralyth later tears apart Gabriel's descended form with darkness tendrils, weakening the snowstorm. Orin defeats Nero again. Nerissa descends to save him and nearly kills Orin by holding him in place with water and crushing pressure.
Lucilla turns on Nerissa at that moment. She severs Nerissa from the God Realm and unmakes her, leaving Nero's wave shard dimmed. Orin moves with Lucilla afterward to stop the remaining combatants.
Aftermath
After Nerissa is unmade, Kalyx remains active above the Erenmyr coast. Kalyx, empowered by Gabriel's crystal, releases an unstable buildup of essence after Seralyth brings him down. Brynor carries the shielded essence bomb underground and seals the fissure above him, telling Orin to look for him someday. Brynor remains missing afterward.
Nerissa's Invasion of Xalmyrra removes Nerissa from Raphael's side, exposes Lucilla as Isandriel's daughter and an unmaker, and leaves Theryssa and Thiravos politically ruptured by their goddess's attack on Xalmyrra. Xalmyrra survives Nerissa and Gabriel's assault. The tsunami, snowstorm, fissures, skyship weapons, and Kalyx's unstable essence bomb cause severe coastal damage.