Kaiōken

Kaiōken (怪凹剣, Wondrous Hollow Blade) is a technique.

Usage
A technique unique to the Fullbringer,. The Kaiōken is a technique Kūgo channels through his, and pierces his opponent in the chest, where the would be located on a Plus, or the  and  would be located on a  or another being with spiritual powers. With this blade, Kūgo displays the very Hollow-like ability to devour the spiritual power of the pierced target; the Kaiōken is capable of absorbing both Fullbring and Shinigami powers. After the power has been absorbed, the technique leaves no wound.

It appears to be the reverse of a Shinigami's ability to transfer power, and stems from the Hollow reiatsu within Kūgo that manifests as his Fullbring. Despite its formidable power, it cannot drain all of the power from a target, as was left with bare remnants of his Fullbring capability, which later merged with his Shinigami abilities and boosted his power significantly. Furthermore, the ability appears to be temporary, as Kūgo lost the Shinigami abilities he stole with it.

According to, Kūgo devoured the powers of many Shinigami with this ability.

Trivia

 * The Kaiōken's name originates from the Dragon Ball series, and was a technique used by Son Gokū to boost his own power. In Dragon Ball, "Kaiōken" is read as "界王拳" (Fist of the World King).