Superhero supporting casts can oftentimes change from creator to creator. Its not that uncommon. Yes, some aren’t going anywhere. Superman will always have Lois Lane, Jimmy Olsen, and Perry White. Batman will always have Alfred and Commissioner Gordon. Spider-Man is going to be weighed down by Aunt May and J. Jonah Jameson for all eternity. But lesser supporting cast members can come and go, sometimes without warning. When writer William Messner-Loebs was working on The Flash, Wally West had a huge supporting cast of friends that succeeding writer Mark Waid decided were only sporadically useful at best and largely ignored aside from the Pied Piper. Loebs had Wally and Linda Park say hello to each other at a mutual friend’s wedding on his last page, and aside from her and Piper, Waid built a new supporting cast made up more of various other speedsters. More egregious would be how Judd Winick gave Kyle Rayner a gay friend, Terry, during his Green Lantern run. At the end of one issue, Kyle appeared to die and Terry got his power ring…only for returning writer Ron Marz to come in the very next issue to see Kyle alive, well, and with the ring on the very first page, and some dialogue how sometime between issues Terry had simply returned the ring and that was that. Terry was never seen again.
Then there was the Alpha Centurion. No one really knows what happened to that guy.