Way of the Empty Palm

Acquisition
Signet of Capture:
 * Ilidus of the Empty Palm (Boreas Seabed (Explorable))
 * Senkai, Lord of the 1,000 Daggers Guild (Boreas Seabed (Explorable), during The Halcyon Job)

Trivia

 * "Way of the Empty Palm" may refer to the martial art of Karate, which translates as 'empty hand'.