Masakazu Yamahisa

Age: 31 (currently)
Birthday: April 11, 1987

Masakazu Yamahisa is Ryu Shizuka and later, Ko Aoki's editor. He works with Ryo to get mis manga more Weekly Shounen Jump friendly and offers Aoki to work on a manga with romance in it suitable for the magazine.

(Source: Bakuman Wikia)