Sadaso

Background
Sadaso is one of the three fighters that challenge Gon and Killua on the 200th floor of the Heavens Arena. Having reached the 200th floor without the use of Nen, he was "initiated" after being attacked with a malicious aura attack and lost his arm. In Nippon Animation's adaptation, Sadaso has both arms intact.

Nen
Sadaso's ability is a Transmuted left arm using Nen replacing his missing real left arm, which was presumably lost when he was "initiated" with Nen upon reaching the 200th floor. 殺大索