Mafumafu is a famous Utaite. The definition of Utaite from https://utaite.fandom.com/wiki/Utaite , a Utaite (歌い手) is a Japanese term for people who cover previously released songs and post them on Nico Nico Douga and YouTube under the utattemita category. The term "utaite" is unique to Nico Nico Douga singers, making it different from Kashu (歌手), which means "singer" in general.
Mafumafu often collaborates with Soraru in a unit named After the Rain.
Note: Ordering this Nendoroid from Animate got the purchaser one of three different can badges. One was of Mafumafu with cat ears sitting in a cardboard box, one was of him sitting eyes closed (the background was green), and then there was this one of him singing. We aren't sure if it was random which one a customer got or if there was some specific qualification that determined which badge the customer received.