Youmei no Kusari is sealed as a long bamboo pole.
When Mikasi utters the release command "Connect... Youmei no Kusari.", the bamboo pole begins glowing and falls slack. It wraps itself around Mikasi's forearms and becomes a metal chain with a spike on each end.
Mikasi is able to command Youmei no Kusari to his will. He normally throws the chain so that the spike on the end will stab into the opponent. The spike will usually pierce right through the mask of a Hollow. With Mikasi's ability to manipulate the chain, he can determine its path in the air, ensuring that the spike does not miss its mark. If Mikasi needs more length on the chain, he can unwrap it from his other forearm for some added length. And if the chain is damaged in any way, it can regenerate.
So far, Mikasi has only mastered four rather simple attacks with his Zanpakutou, mostly due to his heavy sleeping.
- Bring Her In - After the spike stabs into an enemy and sticks, Mikasi can pull the chain in to bring the enemy closer to him. When the enemy is close, he can attack them with the other end of the chain. However, Mikasi is not as strong as he looks, so it is difficult to pull stronger or heavier enemies in.
- Round The World - When the spike stabs into an opponent, rather than pulling it out, Mikasi will instead begin swinging the enemy around on the chain. When the spike pulls out, the enemy is launched through the air.
- Shackled Prisoner - With a mighty swing of the chain, Mikasi can completely wrap an enemy up in it, restraining them. If the enemy is strong enough, they can break free.
- Chain Mail Armor - Mikasi can completely wrap himself in his chain, granting him very powerful armor. It has trouble blocking direct physical impact-based attacks, but can easily deflect projectiles and bladed weapons. Energy-based attacks are also not very effective on the chain armor.
Mikasi has not achieved Bankai.
Youmei no Kusari's spirit takes the form of a scarred and weathered-looking man dressed in the gear of an American army general. He often acts as if he is a general and Mikasi is one of his lowly men. He is quite angry and easily irritated, a sharp contrast to Mikasi's laid-back demeanor.