I think Satoshi Igarashi is
MuryokuP a.k.a. Powerless
- They have the same birthday
- Powerless tweeted in 2013 that he got a job in Osaka
- Igarashi joined PlatinumGames in 2013 (located in Osaka)
- Powerless has been retweeting Astral Chain news
Picture of Igarashi's workstation (April 2012)
Picture from Powerless twitter showing same equipment (March 2012)
EDIT
Cached page on Deezer from a Diverse System album (no longer up)