Musashi  

Musashi was one of many individuals attempting to master Genkais techniques. During the fourth test, he faced off against Kuwabara and unfortunately lost. Despite this setback, Musashi possesses a unique ability that allows him to conceal his spirit emissions in the dark, making it difficult for others with high spiritual awareness (like Kuwabara) to detect him. Additionally, Musashi wields a sword made from a sacred tree that has been washed in a holy stream. A fragment of this blade was used by Kuwabara and granted him his Spirit Sword abilities.