Hachiyama Yumi (in Japanese 蜂山有実) was a really cool member of Muchi Muchi Anago, best known by his real name Amano Tonbimaru. He was another dancer and chorus on stage, but he was also in charge of guitar for the recordings.
He usually had Mona (the 2channel cat) with him. Super cute. He was the vocalist of the awesome band Guruguru Eigakan.
Unfortunately he died on August 12, 2013. You'll always be missed, brother.