Len is a mysterious, cat-like familiar and a supporting character in the Melty Blood series, which is set in the Tsukihime universe. She is closely associated with Shiki Tohno and appears as a quiet, enigmatic presence with supernatural abilities. Len can manipulate dreamlike spaces and is strongly tied to the surreal, otherworldly tone of the story. Although she often seems reserved and detached, she plays an important role in the narrative by revealing hidden connections between characters and the strange forces influencing the events around them.