Summoning the Holy Sword? There were many swords bearing the name of the Holy Sword in Vaun, like the Wind Crown Nodaxis, the Endless Sky Sword, and the Mountain's Holy Sword 'Extreme,' as well as the only one ever obtained by a player—Hu Po. However, in Brand's mind, these legendary names had nothing to do with him.
Is this a spell? He knew that the Priest had a low-level Light Magic spell called Holy Sword Skill, but that spell had a series of pure offensive runes and clearly had nothing to do with summoning or calling. In the game, words imbued with magic power were taken very seriously and could not be arbitrarily altered or combined.
But regardless of what this summoning of the Holy Sword was, Brand knew that any spell available for players to use in the game had no severe side effects at most— the worst consequence would simply be overexertion of spiritual power, which wouldn't cause splitting headaches, only mild mental fatigue at the most.