Berserk

Berserk (怪力無双) or Unequaled Strength (怪力無双) is a Unique Skill belonging to Hiiro. He awakened it as a young boy trying to defend his village from an Ogre Bear.

Abilities
The exact nature of Berserk is unknown, but it seems to increase the user's physical strength immensely.

Trivia

 * In Isekai Memories, Berserk serves as a Battle Skill for Hiiro [Scarlet Bond]; using the translation of "Total Chaos".