Thanos' Brother Starfox Formed Marvel’s Dark Guardians of the Galaxy
In order to stop Thanos from being reincarnated after Gamora killed him, his brother Eros (aka Starfox) assembled his own team of heroes called the Dark Guardians. In Donny Cates, Geoff Shaw, Cory Smith, and David Curiel's run on Guardians of the Galaxy, Eros formed the team out of some of the most badass characters from across the galaxy. The Dark Guardians consisted of Wraith, the Cosmic Ghost Rider, Gladiator, and Nebula and were led by Thanos' older brother, Starfox.
The Dark Guardians were born out of necessity, as Eros learned after Gamora sliced off her father's head, Thanos would be resurrected in someone else's body. Starfox was badly scarred after the Black Order stole Thanos' body during the reading of his will and detonated a device that nearly killed him. With Thanos' resurrection in play and not knowing who's body the Mad Titan would takeover, Starfox assembled the Dark Guardians. The team would search across the cosmos for the potential person Thanos would become, which led them to a few familiar faces.
The Dark Guardians consisted of heroes who didn't want to see Thanos return. The Cosmic Ghost Rider saw what happens when Thanos wins, as he served him in Marvel's dark future. Nebula grew up as Thanos' personal science experiment. Meanwhile, Gladiator saw the damage Thanos could do across the universe and offered assistance to prevent him from ever returning. Lastly, Wraith had a personal mission: he wanted information on Knull, the God of Symbiotes, which Starfox promised to provide if he helped stop Thanos.
The Dark Guardians would track down Richard Rider (Nova) in hopes he could provide information on Gamora's whereabouts, believing Thanos was going to take over her body. He refused. The Dark Guardians even sparred with the Guardians of the Galaxy, nearly killing Peter Quill, who didn't want to give up Gamora either. Eventually, the Dark Guardians captured Gamora but soon realized Thanos planned on taking over Starfox. In a massive battle with the Black Order, Starfox would be killed by Gamora, and Thanos (resurrected with a broken mind, later fixed by Phastos) would be sucked into a black hole - effectively ending the Dark Guardians time as a team.
Starfox's Dark Guardians nearly accomplished their mission and stopped Thanos' resurrection. However, unbeknownst to Eros, it was his body his evil brother intended on taking over. Ultimately, Thanos cost Starfox his life. However, as an Eternal, it's likely the character will be revived someday through the Great Machine - if he hasn't already been brought back to life. If Starfox ever comes to the Marvel Cinematic Universe, it would be a lot of fun to see the Dark Guardians team and storyline come to life on the big screen - as it would be the perfect way to bring back Thanos, even temporarily.