Kenshiraha is sealed as an ordinary-looking tanto. This sealed state was necessary due to Umi's small size.
When activating Shikai, Umi holds the Kenshiraha tanto in front of her, near her chest, pointing up. This is similar to how Byakuya Kuchiki holds his own Zanpakutou when he releases it. Umi utters the words "Flap your wings... Kenshiraha." At that command, the Zanpakutou explodes into a mass of pure white feathers that fill the area. The white feathers hang in the air all around the area for a few moments, then rapidly gather at Umi's back to form pure white wings.
While Umi cannot fly with her Zanpakutou wings, she can float above the ground a foot or two. Hovering like this offers Umi a much more stable and swift method of movement than running, allowing her to read or fiddle with something in her hands without being disrupted by the jarring motion of running. Umi is also able to make sharp turns this way, and can move sideways and backwards without having to turn around or slow down. She can even hover over the surface of the water, and temporarily and briefly glide across gaps.
But Kenshiraha's real strength lies in the feathers. Using her Reiryoku, Umi is able to harden and sharpen the feathers. This allows her to pluck feathers from her wings, sharpen them with Reiryoku, and throw them at targets like throwing knives. Umi is able to throw an unlimited amount of knives this way.
Umi has also mastered several powerful techniques using her wings.
- Feather Guardian – By wrapping herself in her wings and hardening the feathers, Umi can guard against most attacks. The defense has so far been able to withstand both massive physical beatings and destructive energy attacks.
- Feather Barrage – By flapping her wings forward, Umi can send a barrage of sharp feathers flying at a target.
- Heavenly Spin – This begins similarly to Feather Guardian, with Umi wrapping herself in her wings. Once her wings envelope her, she hardens and sharpens the feathers, and begins spinning in place. After picking up speed, Umi begins moving across the ground. If Umi hits a surface, she will bounce off of it, picking up speed like a pinball. Being rammed by this attack at even medium speed feels like getting ran into by a tank.
- Heavenly Drill – This technique is essentially the horizontal version of Heavenly Spin. Umi wraps herself in her wings, hardens and sharpens the feathers, and begins spinning. But then she tilts horizontally, spinning like a drill. This allows her to actually fly around by drilling through the air. However, movement is somewhat difficult to control. The attack is said to be able to drill through almost any hard surface, but it takes a large amount of Reiryoku to maintain.
- Ivory Pandemonium – Possibly Umi's strongest technique she's mastered with her Shikai. It is essentially a combination of Heavenly Spin and Feather Barrage. Umi wraps herself in her wings, hardens and sharpens her feathers, and begins spinning. However, Umi stays in place as she spins. The spinning begins to pick up winds, and Umi releases a storm of sharp feathers that blow all around the area, bombarding anyone or anything around her with deep cuts. The technique is dangerous to allies, so Umi rarely uses it.
- Everlasting Rainbow - It is a beautiful techique that begins by making Umi's wings glow. The energy is charged up and released with suprisingly explosive energy. The technique uses her life essence making it very risky. The move's power increases by her urge to protect someone. When she used it she was thinking of protecting Zukia Tojiro making it highly powerful, Asesino stated that it was a potent attack that not even he could dodge.
Umi has not achieved Bankai.
Kenshiraha's spirit is a tall blonde man dressed in a red coat with many buckles and straps on it. His face is stern, and he appears to be at least in his late thirties. He bears large white-feathered angel wings on his back, and wields a large double-edged sword. He refers to Umi as if she were his daughter, and he her strict father.