Kidou Senshi Crossbone Gundam: Skull Heart

The manga consists of a series of individual stories, centered on the exploits of the Crossbone Vanguard during and three years after the end of the original series, with one exception; the first story is set during the One Year War and deals with Crossbone pilot Umon Samon's youth. The series also features the "return" of Grey Stork, the aged future version of Judau Ashta, who previously appeared in Hasegawa's V Gundam Sidestory manga.

(Source: Wikipedia)