Bloody Strings is a Magic Skill. See Skills for more information.

Bloody strings Bloody Strings

Sacrifices an ally to increase caster's Attack Power, Critical Rate, Multi-Hit Rate, reduce Combo Count by 1 each turn and grant immunity to Magic, except Purification and Dispel.

Increasing Skill Levels: Edit

Via Skill Books: Edit

You can increase Skill levels using Skill Books:

Via Atlas Ore: Edit