Gleipnir

Gleipnir is a Manga/Manhwa/Manhua in (English/Raw) language, Seinen series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.com fastest updating comic site. The Summary is

Shuichi Kagaya isn’t human. He has an unnatural sense of smell, and can transform into an incredibly powerful beast... of sorts. He does all he can to avoid standing out and being discovered, but no good deed goes unpunished, and his decision to use his power to save a girl spells the end for his quiet life.