Black Flame

Black Flame (黒炎) is an Extra Skill Rimuru acquired alongside Molecular Manipulation when fusing Flame Transformation, Fire Manipulation and Water Manipulation via Unique Skill Degenerate.

Abilities
It allows the user to release very destructive Black Flames from their body. The technique uses one's internal Magicules, and the maximum size of a flame may reflect on their user's power.

By creating a field of magic, transforming it into flames, and then launching it away, fire can be created from thin air. The temperature of the flames can be adjusted based on how much magicules is used.

Black Flame is also one of the base Skills for Hell Flare.

Trivia

 * In Veldora's Journal, Veldora mentions that Black Flames are "his flames," though probably in a way that's different from the specific Extra Skill Black Flame.