Black Fish

Black Fish is a Shinsoo technique that Scouts use to block out the light of a Lighthouse. This allows the Scout to become "invisible". This is used to both hinder the attack of Fishermen and Spear Bearers and is just as important to help the Scouts' observers as they like darkness.

Of course, the Light Bearers can use reverse techniques to counteract the blocking spell.

Trivia

 * SIU has a notable love for aquatic life, the name of this technique being one of many examples.
 * Black Fish's Korean name, "Heuk-rin", means that like a waving black feather, it blocks out the light.