Gehenna Blaze is a transcendental skill that has one of the highest transcendental values required for the fire-only attribute. It is strategically wise to use if trying to target only one individual, as it uses very little vigor to perform. However as it lacks any explosive power or penetration, it is rather unwise to use to fight against multiple enemies at once.
In Season 1, Kasak Rajof uses this skill which targets Hura during the battle at Atera. It was likely at this point in the fight when Kasak began to suspect that Hura was diverting his attacks on other targets to himself.