While MCU film Avengers: Infinity War, their characters weren’t very well developed beyond their villainous actions, and a dark rivalry that was present in the comics wasn’t seen by MCU fans at all.
The Black Order, also known as the Children of Thanos or the Five Dreadlords, consists of Corvus Glaive, Ebony Maw, Proxima Midnight, Black Dwarf, and Supergiant, with Gamora a key member of Thanos’ army as well. They made their first appearance in New Avengers #8 by Jonathan Hickman and Mike Deodato where the Black Order is immediately presented as a world-ending threat alongside their master, Thanos, who is working to conquer Earth. Together the Black Order are some of the fiercest warriors in the cosmos, though they don’t always have each other’s backs. In one particular storyline–one in which the team itself is a bit different than the original lineup–there is a very serious power struggle going on right under Thanos’ nose that is never even hinted at in the MCU.
In the six-issue miniseries Thanos by Tini Howard and Ariel Olivetti, fans are given the full history of Gamora’s time working under her adopted father, Thanos, before he was killed by her many years later. The first issue depicts Thanos brutally killing everyone on Gamora’s home world before finding her hiding away in her home, seeking refuge from the violence. When Thanos discovers the young Gamora, he doesn’t kill her as he has done with everyone she cares about. Instead he takes her as his own daughter as at this time he is collecting people across the galaxy to him in his conquest for power and death. When Gamora is forced to the team after Thanos invades Gamora's home world, she is not accepted by the others, though one member of the Black Order, Ebony Maw, sees a potential use for her.
Throughout this series and beginning when Gamora was a little girl, Ebony Maw constantly threatens her life in an effort to intimidate her into listening to him, hoping to use Gamora to influence Thanos. From her first night on Thanos’ ship, it is clear that he has an infatuation with Gamora as he allows her to speak freely with no consequence and works to train her in the ways of combat. As much as he can, Thanos actually shows signs of caring for Gamora, and Ebony Maw knows he can use that to his advantage. However, Gamora has never been a pushover and even stabs Ebony Maw with a fork the first time she meets him, so his consistent efforts to try and use her for his own benefit and her not having any of it just create a bitter rivalry that goes on for years.
Ebony Maw and Gamora barely share a scene together in the MCU and nothing hints at the fact that these two of the Black Order were rivals in the past. This dynamic could have been used to further flesh out their characters and add another reason for Gamora to turn against her father. However, in the comics, that rivalry is made abundantly clear and is an interesting tidbit about Thanos' Black Order that MCU fans never got to see.
