Fan Theory About Star Lord's Possible Sister in GUARDIANS OF THE GALAXY VOL. 2

There is a rule in science fiction that everyone must be related unless stated otherwise. It all started in Star Wars with Luke and Leia. When Darth Vader became Luke's father, that was one thing, but then the twist out of nowhere that Leia was Luke's sister? Bam. Now, the cool thing is that everyone's related. Look no further than The Force Awakens. Once the movie came out, rumors abounded that Finn was Lando's son, Rei was everyone's daughter, and BB-8 was the adopted grandchild of R2-D2. Well, add another possible relation theory to the list, but now in Guardians of the Galaxy.

The theory goes that Star-Lord aka Peter Quill has a sister in the second film. It's one of the new female characters in the story, Mantis. With Mantis being Ego's right-hand lady, it would make sense that she too might be one of his many offspring. But unlike the hundreds upon thousands of children that he killed, she had a use, so he kept her around. With her being the child of Ego from another mother, that would make she and Quill half siblings.

While there is a lot going for this theory, including the random happenstance that Ego just picked her up, there really is very little other evidence than that. There is a galaxy full of people. Why would they be siblings? Why not just tell Star-Lord in that moment that they are brother and sister. Help ease his tension, maybe? However, if Ego did sleep with every species in the galaxy, and have children with each one, why not just take his own child that is of Mantis' race. Unless of course, it was one of the few relations that just didn't work out for Ego, considering Mantis' species usually eat the male after mating. 

I personally believe the story that Ego found her on a planet, the last of her kind. Why lie about something like that? And if she is the last of her kind, maybe he was waiting to use her as, well... for things other than sleeping. If you know what I mean...