There are more than one artist under the name Reiner:

1) Reiner is a Latvian melodic punk band from Rīga, Latvia. The band consists of vocalist Mārtiņš Vaters, guitarist Rūdolfs Rūtenbergs, bassist Raitis Radiņš, and drummer Miks Riekstiņš.
The band self-released their debut EP Veidojot tagadni in July 2019.
Associated acts are Ambrosia, IndyGo, and Nekad.
http://www.facebook.com/reinerband

2) Reiner ia a project from Belém do Pará, Brasil that plays experimental music. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.