Vaporizing Rebellion Sword is the last technique Luka learns in part 2 of Monster Girl Quest. Unlike all the skills taught to Luka by that point, it is instead taught to Luka by Salamander. This skill replaces Death Sword Chaos Star.
Vaporizing Rebellion Sword is an attack which hits for 5 times, as opposed to Death Sword Chaos Star's four. It also does more damage than Death Sword Chaos Star, and can be boosted in terms of power if Salamander is an active spirit on Luka at the time.