Soap Bubble Ninjutsu

Utakata uses Soap Bubble Ninjutsu from the of ninjutsu. He seems to use a special pipe to create his bubbles.

This line of ninjutsu allows Utakata to float inside his bubbles, as well as use them offensively by trapping his enemies in them, filling the bubbles with an inky black substance, and subsequently popping them, killing whoever is inside.