Borg

Bolg (防壁魔法, Borugu) is said to be the proof of a Magician. It is a defensive ability. It blocks out attacks with evil intentions. It also blocks out all physical attacks and magical attacks to some degree. It's strength, however, depends on the person. According to Myers, if the Bolg is attacked by immense physical strength, then it can be crushed/destroyed.

Trivia

 * Ugo is the only person capable of crushing a Bolg with physical strength seen to date.
 * The Magic Ugo is also able capable of destroying Bolg with physical strength.
 * When translated from kanji, Bolg (防壁魔法) means Magic Barrier.