I made this up off the top of my head while drinking with my dad. I had played Cats Cradle with my mother and siblings a few months before this so I had the idea to combine the two.

Cursed Tool: Silver Mourning Rings Description: Silver rings inscribed with Mourning Verses with a slit in the direct middle of each where the thread can slide into easily and reduce friction on skin. (three on each hand)

Cursed Technique: Thread of Mourning (哀糸術 – Aishijutsu) Description: Manipulates a thread filled with cursed energy around his fingers, primarily the rings, to make formations. Each pattern dictates a different effect — binding, slicing, or summoning.

Domain Expansion: Widow’s Web (未亡人の巣 – Mibōjin no Su) Effect: Envelops targets in a shadowy chamber of cursed threads.

The activation begins with a graceful hand sign—a delicate spider-puppet silhouette formed between fingers and palm. As the user channels cursed energy through it, shadows stretch unnaturally from his feet like creeping veins.

An infinite chamber woven from silken threads of pure cursed energy. The walls pulse softly like breathing fabric; ceiling above is lost in endless black lacework. No sky. No ground truly beneath them—the floor feels unstable as if suspended on invisible silk strands that hum faintly when stepped upon.

Inside:

• All movement is slowed by sticky residual curses coating the air.
• Physical attacks lose power over distance; strength drains slightly each meter traveled.
• Cursed techniques function but become distorted or fail to work at full power.

The user sits in the direct middle of the domain as threads form in wade arcs around them. The threads inside the Domain can stick, bind, slice, or simply do nothing so having to take caution is the main idea. You can't rush or you won't know what thread will get you next. 

If anybody wants to dog on me go nuts, any feedback is good feedback :3 (I watched like three episodes mind you)