1. She has an English accent.

So far in the “Star Wars” films, Rey and Obi-Wan are the only main characters that have accents that sound English. None of the Skywalkers have the this accent, so the person who raised Rey couldn’t have been one of them. John Boyega has a English accent in real life; he spoke with an American accent for the films.

“It made him more grounded as a character… It felt like a natural, good choice,” said Boyega, according to blastr.com.

2. She uses the Jedi Mind Trick.

During her captivity, Rey uses the Force to control a stormtrooper to release her. Obi-Wan is the only other character to be seen using this trick besides Rey.  If the Force is passed down through families, could a Mind Trick be passed, too?

3. Luke wouldn’t break his Jedi vows.

After what happened to his father, it is very likely that Luke wouldn’t break his vows and become attached enough to father a child. Since he learned the story of his father’s fall to the dark side, he hopefully wouldn’t feel like having his own family.  When we first met Obi Wan he was a lonely hermit in the desert and being secretive about his Jedi past. After the Jedi Order was destroyed, Obi Wan didn’t have any more vows to uphold anyway and quite possibly could’ve fathered a child in those 19 years. Even though it may not be Rey because she’s too young, he could still be Rey’s grandfather.  

4. Maz Kanata heavily implies Rey’s family is dead.

When she says “Your family is not coming back, but there is one who still could,” Maz insinuates that Rey’s entire family is dead, including her (possibly Jedi) grandfather. Even though her family couldn’t ever come get her on Jakku, the “one who still could” is very likely Luke.

Luke is the son of the man trained by Obi Wan. Spiritually, he is, as far as viewers know, the closest thing Obi Wan has to a son or a grandson, making him likely the closest relation Rey has, without actually being related.