|Full name||Soul Chain|
|Manga Debut||Chapter 25|
Soul Chain is Legato's main fighting technique, the natural form of his dark matter, and the base of his secondary techniques.
Releasing dark matter, Legato appears to shed tears, both of his eyes being being drenched with a dark, liquid substance, which drips down over his face. In his chest, a skull-like image appears, with flaming patterns connecting to the his shoulders. His eyes become snake-like, and four concentric circles appear under the skull image, from which serpentine spirits are released. The spirits are visible only to the user, but as long as they remain around the opponent, it shall restrain the latter's movements. As it affects the target's soul, this technique cannot be broken easily.
Soul Chain was first seen during Chapter 25, where it was used to restrain the movements of a full-powered, transformed Kucabara. Despite Kucabara being able to defeat several dozens of wolf soldiers in his regular form at that time, and even hundreds of them in his transformed state with ease, he was defeated the moment he received the technique, falling on his knees. He was then rendered helpless as Legato delivered a stab to his thorax, at which the Soul Chain's effects were dismissed. Later, Legato manifests the Soul Chain again to complete the deal he made with Kucabara, pulling all of the dark matter out of him and into his own body, growing taller. The technique was not as effective in Kucabara during their second fight, as he was able to move a little while bound.
Red Soul Chain Edit
In his brief confrontation against Garypeter Sugal (who was attempting to protect Jupiter in order to stop his plans), Legato used a variation known as Red Soul Chain (レッド・ソウル・チェーン, Reddo Sōru Chēn), with which he destroyed the opponent's blades. This technique can be used without much preparation, as all that Legato needs to do is to close and open his eyes, dripping much less of the substance than in the original technique. It seems to be weaker than the usual Soul Chain, due to its lack of preparation, but the target is lifted into the air at its execution, causing a loss in balance. In order to compensate for any weaknesses, Legato makes so that the serpentine spirits explode around the opponent, causing an effect similar to Kucabara's Eternal Cycle. With this technique, Sugal was incapacitated for hours and heavily wounded.
Soul Chain Blade Edit
Legato used the Soul Chain Blade (ソウル・チェーン・ブレード, Sōru Chēn Burēdo) during his fight against the transformed Kucabara over the demon world's capital city white in the air. It consists in the quick usage of the regular Soul Chain with all of its preparation, generating the serpentine spirits to bind the opponent in place. After that, Legato slashes the target with an edged blast formed by using his sword and the technique's dark matter at long range. The slash was dodged by Kucabara, who had the ability to move freely in the air, but whether this was allowed by Legato or the surpassing of the technique's power, it is unknown. After dodged, the slash hit Bchuler, causing a clean cut right through his body. That wasn't enough to cause the dragon's death, but the finishing move of the technique was a deadly stab in the heart.
- The serpentine spirits used in the technique are similar to those seen inside the kelsa killed by Kucabara, although in that case the spirits were visible.