Cursed technique: "Shinso Jiko no yami no kaiju" (Mysterious Beasts from the Deep Abyss)
This technique summons shikigamis in the shape of non-fish abyssal creatures. Those shikigamis are always trying to take control of the user's mind. The shikigamis range from sea urchins, crabs, narwhals and dolphins to a lovecraftian abomination called "The Deep Elder of the Deep Beyond", which applies RCT to the user and gives them an infinite pool of CE, but making the user fall unconscious for periods that can stretch weeks about 30 seconds after activating the ability due to the overwhelming mind of the elder. The RCT continues flowing even if the user's head is blown off as it is the elder who applies the RCT.
Another derivative of this technique, so it isn't "10 shadows+jackpot" is the addition of "Perspective matters", a condition in which if it's user closes one eye, everything they see is reduced to a 2D plain, and every hit that looks like it's coming towards you will hit you, no matter if it's way behind or in front of you, all that matters is the angle relative to the user. This also hits the soul, as this techniques user has trained w/ Nobara's grandma in her pilgrimage through japan to learn the best CTs, being a resonance between her vision of the opponent and the opponent.
The domain, "The deep abyss of deep beyond" is pretty unique, as it creates a 10 meter barrier that collapses and sends its user and everyone else in the barrier into the cursed realm. The domain is initially a 100 meter sphere centered on the user and target, but the moment anyone tries to escape, the domain stretches in their direction, with everyone having a 100 m domain sphere around them. If the spheres would disconnect, the space among them collapses and makes it so both spheres are always connected.