According to IGN on April 2, Karen Gillan, who will be playing Nebula in James Gunn's "Guardians of the Galaxy", talked about her role as the servant to Thanos. Also, the prelude comic, available from Marvel at Infinite Comics, will focus on Gamora and what makes her tick. There are also tie-ins with Thanos' relation to Ronan the Accuser as well.
Gillan explains the relationship between her character and Gamora as that of sibling rivalry. That being said, at least according to comic book lore, Nebula had claimed to be the granddaughter to Thanos and Gamora as the adopted daughter.
Both ladies are rather fierce as seen demonstrated in the movie trailer and Gillan talks about the bickering that occurs between the two.
"There's definitely some rivalry going on between those girls," Gillan said. "Absolutely! And they're both extremely fierce women and so when they bicker it's like...Imagine two sisters bickering and pulling each others hair, well they fight like assassins. I think that there's definitely a need to impress. But they both have different motivations for that, and I would say that Gamora's more on the good side and Nebula is very much on the dark side".
Nebula was known to have assisted Thanos in combining the Infinity Gems to form the Infinity Guantlet with is an artifact of omnipotent and god-like power. It was seen gemless in the first "Thor" film, but it appears this may all come together as the Marvel Cinematic Universe continues forward.
Both characters had trained under the guidance of Ronan the Accuser who at one time worked with Thanos. So it would seem Gillans idea of their relationship seems to have a simliarity to what's exhibited in the "Guardians of the Galaxy" prelude comic book.
"Guardians of the Galaxy" opens in theaters come Aug. 1.