Overview
The Glaive of Frost and Fire is a fire-and-ice artifact in a bootstrap loop involving Viviana and Pyrathalor. Vianna receives it beneath the Ember Spire, carries it through the Varnhallow displacement into the past, and gives it to the obsidian being who becomes Pyrathalor.
Because of that loop, Pyrathalor's older glaive and Vianna's newly forged glaive coexist until Vianna takes the younger weapon into the past. The older instance becomes the divine weapon that nearly kills Cassian outside Chronasis and later passes to Aelius.
Form and Use
The glaive responds to Vianna's paired fire and ice immediately. Flame runs along its length, and frost winds through the weapon in matching patterns. After Viviana gives it to the obsidian being in Radiance Prime, he melts and reforges it with a longer shaft and wider twin blades.
In Pyrathalor's hands, the glaive burns with molten force on one side and carries impossible frost on the other. His strikes can liquefy terrain, carve the ground open, and tear through powerful shields. When Cassian retrieves the recovered weapon from Chronasis storage, it is nearly as tall as he is and channels essence along its shaft and edges.
Aelius uses the recovered glaive as a plasma focus. He channels plasma along its handle and edges, throws it in combat, combines its weight with fire propulsion, and uses it with resonance-wave spells.
History
Vianna first receives the glaive beneath the arches of the Ember Spire. She uses it during the Brighthaven strike against Alistair and later carries it through the invasion of Thalassai. In Varnhallow, she leaves the weapon behind because the tournament bars weapons; Zayren retrieves it during the collapse when he rescues Dorian and Rowenna. When she is displaced into the past, she gives the weapon to the obsidian being in Radiance Prime shortly before helping awaken the burning frost crystal. The fire-and-frost eruption creates Pyrathalor, who keeps the reforged glaive and brings it to Morozkaya.
Pyrathalor still carries the weapon in the present, including when he confronts Thalena outside Chronasis. Thalena traps him with a black hole. He launches the glaive through the golden barrier and into Cassian's chest. Astryx removes it during Arinella's healing attempt. Thalena's time spell keeps Cassian alive long enough for Arinella to rebuild him.
Afterward, the glaive remains in Chronasis storage. Cassian offers to return Pyrathalor's glaive to Vianna. She refuses it and insists that Aelius keep it. Aelius accepts the weapon and uses it in later training and combat.