The grave is a powerful symbol of a lost connection. Even if players state very clearly on their PC character sheets that they have no family connections, and you feel that resurrecting them or otherwise having relatives pop up unexpectedly isn't playing fair, you can still bring bring home an emotional connection by introducing the grave.

Harry Potter did it quite effectively.

Or you can always go the other way and riff on Pet Sematary or Poltergeist...

Transcript

Luke: When Obi-Wan took me out into the Galaxy, I never thought he'd get killed! Who's going to train me now?
Han: Hey kid, I can teach you everything I know.
{beat}
Luke: What am I doing here?
Leia: You whinging little snot.
Leia: You're the child of the Chosen One! It's up to you to save the Galaxy!
Luke: Me?!
Leia: You got more reason to hate the Empire than anyone.
Leia: Dad told me the legends. Your old man Anakin turned evil and murdered your mother, Padmé.
Luke: Obi-Wan said. And then he killed him.
Leia: Yeah. Anakin died on Naboo during the Droid Wars.
Luke: Naboo? The planet the Peace Moon blew up?
Leia: That's not all. Naboo was Padmé's home world. She... was buried there.
Luke: Seriously? I find out I was adopted by nutcases, my real dad died some sort of war criminal, and my mother's grave was desecrated to the max?
Leia: Doesn't that make you angry?
Luke: I'm livid!
[SFX]: < bippity bippity squee be-oomoo >
R2-D2: Good. Good. Let your hatred glow.