Keychain | Hunter x Hunter | Kurapika Nen

Kurapika can conjure a unique weapon—five chains that extend from each finger on his right hand. Some of the fingers were specially designed to deal vengeance on the Phantom Troupe. To increase the effectiveness of his chains against them, Kurapika placed strict Limitations on the usage of his chains. Since the chains are materialized, their size and length can be controlled to a certain degree. He is able to conceal his chain through In in order to bind his opponent without their knowledge until it is too late. Kurapika is also proficient in other branches on Nen, such as Shu, which, combined with Emperor Time, gives his chains the ability to shatter rock, and Gyo.
(From Fandom Hunterpedia)

Hunter × Hunter (ハンター×ハンター, Hantā Hantā), pronounced "Hunter Hunter", is a Japanese manga series written and illustrated by Yoshihiro Togashi with two anime adaptations. The first chapter of the Hunter × Hunter manga series was published in March 1998, in Weekly Shōnen Jump.

The story of Hunter × Hunter focuses on a young boy named Gon Freecss, who one day discovers that the father he has always been told was dead is alive and well. He learns that his father, Ging Freecss, is a legendary Hunter. Despite the fact that his father abandoned Gon with his relatives in order to pursue his dreams, Gon becomes determined to follow his father's footsteps, pass the Hunter Exam, and eventually find his father to prove himself as a Hunter in his own right.

(from Fandom Hunter x Hunter Wiki)