If you're unfamiliar with these games, here are the rules: three men or women will be pitted against each other and you are forced to place each of them into a specific category of your choosing. You cannot double up on any category, replace people, or anything else. You must pick one to "Wed" (marry), one to "Bed" (have sex with), and for "Dead" (kill)—in theory, of course.
Having just watched this movie the other day, these characters are still very fresh in my mind. Technically, there are five main women in the cast if you count the villain Ayesha and Peter's mom, Meredith Quill, but these are the three who show up the most and are essentially part of the same team. To be fair, Nebula is not official for a team member, but she might as well be.
This is a pretty strange edition as we have three aliens: one who is green, one who has antennae, and one who is a cyborg. I guess we'll figure out everyone's kinks, right?
Bedroom Invitation = Gamora
Death Sentence = Nebula
For these games, I like to use a three-point criteria of Attraction, Personality and Wildcard. Attraction and Personality are pretty self-explanatory, focusing on their looks and what goes on behind the scenes. Something like their intelligence, character traits, behavioral attitude, and so forth would go under Personality, while their physical appearance and sexiness make up the bulk of Attraction. As far as Wildcard goes, those could be any other factors that take away or add to someone's appeal.
Nebula's body has been contorted in several different ways throughout these two films, so you know she's flexible, but that's still not going to save her from the Kill slot. Her character is the most evil of the bunch and only toward the end of Vol 2 shows any redeeming qualities. Gamora is, at heart, a hero, while Mantis is sweet, so the two of them destroy Nebula on personality points.
Since all three women are attractive and we've devalued Nebula's attitude and such, the question turns to a bidding war between the personalities and physical appearances of Gamora and Mantis. At face value, Gamora is more attractive to me, but there was something cute about Mantis that I think would be much more tolerable to be with on a dating level. Gamora's got a mean streak to her and apparently is super competitive even with her sister's eyeball at stake, so that's going to be cause for plenty of arguments down the line. Mantis is also an empath, so she'd get me, and she has the biggest heart of anyone in this series so far. Since both are good looking and Mantis has the better personality, she gets bumped up to the Marry section while Gamora sits comfortably in the Fuck category.