Bloody Fissure Thunder Thrust (or simply Thunder Thrust) is a skill taught to Luka by Alice after he setting up camp prior to the Leech Girl's defeat. Luka omits the "Bloody Fissure" part, leaving only "Thunder Thrust" because it sounded too "long" and "disgusting".
It consumes 2 SP to use and deals significant damage if used on the first turn; however its effectiveness decreases per elapsed turn.
Thunder Thrust is eventually replaced by Lightning Sword Flash.