I've seen a lot of people take scar's "what happened in third life?" question and interpret it as scar not remembering third life—which makes for a very fun idea
however, I'd like to offer:
scar and grian’s entire interaction is the two of them trying to gauge where they stand with one another. grian’s hesitant “…just like in third life” is a silent question, both trying to discern if scar remembers the desert, and how he feels about it. it’s his hesitant foot forward
scar remembers third life—of course he does. he knew so many of the answers to the questions. he remembers every little detail of that game, because it was probably where he was happiest
he only asks grian “what happened in third life?” because it's a test. he's testing the waters between them, now standing as two victors on equal footing, equal ground. he plays dumb because it's scar, and he never shows every card in his hand, every trick up his sleeve. before scar takes any kind of step forward, he needs to know how grian will explain the desert, what he’ll say about it.
he asks “what happened in third life?” but there’s more questions lying in it. “do you still care?” “am I safe to trust you with my heart?” “did it mean something to you?”
scar is sneaky like that, subtle, as he pretends he doesn’t know or doesn’t remember. he needs to see what grian’s reaction is before they take up their dance again
