Oikage

Oikage (追影, Seeking Shadow) is the Final Secret Sword Technique of Ikki Kurogane.

Description
"Even his own shadow could not keep up with this strike's extreme speed. He was the concept of a slash incarnate. The goal of so many people, the peak they pursued. This final strike, combining the phenomenon and the awe it inspired, would be called thusly by people: Final secret sword - Oikage."

- Oikage as explained in Volume 9

Oikage is a technique Ikki had created after his seven secret swords in the finals of the 62nd Seven Stars Sword Art Festival to defeat Stella, making it his "Final Secret Sword". This is a battoujutsu used right after he activates Ittou Rasetsu, though since Intetsu doesn't have a sheath, Ikki instead place his right hand on the hilt is pushing, while his left hand on the blade is pulling it back resulting in speed on a different level than using a sheath. Once Oikage is unsheathed it possessed such extreme speed that Stella witnessed a white world and his shadow was unable to keep up described as the "concept of a slash".

Alongside his improved usage Ittou Rasetsu, through focusing the strengthening on the most needed parts of him instead of his whole body, putting the excess power into Intetsu; he could also use his powers as a Desperado to influence the causation of "killing" letting cut through Iris' nigh-invincible Orichalcos.

Weaknesses
Differing from his original secret swords, which Ikki became able to use after leaning Edelweiss' Swordplay where he initially needed Ittou Shura, he needs still Ittou Rasetsu to be able to use Oikage, as well as the same motions.

Users

 * Ikki Kurogane

Trivia

 * Oikage is stated to be the peak that other people have attempted to reach.