After finishing the game, I felt a bit lost, or rather unsure of how to take "Luke"'s first words upon returning from the dead. What promise is he referring to? And even before that, who is he? Luke, Asch or a combination of the two?
Some time after Lorelei's releasal and Luke's supposed death, Tear is sitting in a field of selenia flowers, singing Yulia's Grand Fonic Hymn, with Guy standing by. The others show up, asking why the two aren't at Luke's coming of age ceremony. Tear and Guy believe Luke will return. But as the moon wanes, Jade suggests they go. Just as Tear makes to leave, she turns and sees a figure in the distance, coming across the field.
Tear: Why are you here?
"Luke": This place has a nice view of Hod. Also, I promised someone...
From the start, Natalia referred to a promise she and Luke had made when they were children. Luke, of course, can't remember it, being a replica made seven years prior, and therefore not having known Natalia in her childhood. The one with whom Natalia made the promise was Asch, the original Luke fone Fabre. One night, when the party is staying at Sheridan, Asch comes to speak to Natalia, and the two recite their promise:
Asch: ...Some day, when we're grown up, let's change this county. Change it so that no one has to be poor. Change it so that war never happens.
Natalia: ...Let's work to change our country. For the rest of our lives. Together.
Afterwards, Natalia discovers Luke had been eavesdropping on their conversation. Although she knows that Luke is not the one from her childhood, she tells him:
Natalia: You're my dear childhood friend, just like Asch. Let's make it through all this alive and together make Kimlasca good.
Luke agrees to fulfill the promise. But much later, Natalia comes to a realisation that affects them both:
Natalia: (...) I was wrong. You and Asch each had your own path. I'd been trying to tie both of you down with a promise that was no longer valid.
Natalia finally separates Luke and Asch into two different individuals in both her own mind and Luke's. After defeating Van for the final time, she tells Luke once more:
Natalia: Luke...live...please. (...) Not to protect Kimlasca. To live your life, understand?
At this point, Luke is no longer indebted to Natalia, and furthermore recognises that the promise she'd attached to him was a mistake - if the promise still applied to anyone, it would have been Asch.
And then there's the promise that Luke makes to Tear after defeating Van for the final time, right before freeing Lorelei:
Tear: You have to come home. You have to! I'll be waiting...always.
Luke: I will. I promise. I'll come home.
When "Luke" returns, claiming he had "promised someone", it seems after comparing the circumstances of the two promises he'd made above that the most likely promise he was fulfilling was the one he'd made to Tear. However, other evidence suggests that it should be Asch, not Luke, who'd be the most likely to return from death.
Evidence 1: The Cheagle At one point, while the party is in Sheridan, Jade and Mieu speak to the cheagle they rescued from Van's Ortion Cavern fomicry lab, privately. Mieu lends the cheagle his ring, and Jade asks the cheagle a pivotal question: is the cheagle the original, or the replica? In fact, the cheagle is the original. And even more alarming is that the cheagle had actually died in an experiment, but was brought back to life when it and its replica merged.
Evidence 2: Luke Dissipating After releasing Lorelei, Asch falls from the sky and is caught by Luke. Luke begins to fade, as though his fonons are dispersing...
Evidence 3: Asch's Hand ...At which point Asch's hand twitches.
Thus, if what happened to the cheagle happened to Asch and Luke, Asch would have absorbed Luke, leaving him alive by way of Luke's fonons. Likewise, "Luke"'s promise could still refer to the promise Asch and Natalia made.
However, other evidence suggests that the Luke who returns is not Asch:
Evidence 1: His Clothes The Luke that returns is wearing Luke's clothes (albeit a rather tattered version).
Evidence 2: His Sword A back shot of "Luke" shows that he's carrying his sword in exactly the same way as Luke.
Still, further evidence provides more questions on the identity of this Luke:
Evidence 1: His Hair "Luke" suddenly has his long hair back, at about the same length as Asch's.
From the evidence I've gathered here, I've come up with two conclusions as to the identity of "Luke" - and thus which promise was being referred to.
It's Luke Based on the strength of the evidence in favour of this being Luke fone Fabre - the clothes and sword, in particular - "Luke" is Luke. In this case, the opposite occured as to what happened with the cheagle: Luke, the stronger of the two, absorbed his original, Asch.
It's Both "Luke" could be a combination of Luke and Asch. Asch's hand did stir, and Luke began to fade after Lorelei was summoned, suggesting Asch was returning to life and Luke was fading away from it. Also, based on what happened to the cheagle, Asch should have absorbed his replica, Luke, in order to revive himself. Because the Luke that returns clearly has properties of Luke, and not Asch, "Luke" is a combination of both.
Personally and from a narrative perspective, I believe the first conclusion to be true. Firstly, the game's protagonist is Luke, not Asch, and it would be strange, if not completely unsound, for Asch to return instead of Luke. Also, the ending scene was set up in such a way that Tear and Luke were clearly the main characters in it: most of the shots focused on Tear and Luke. If "Luke" had been a combination of Luke and Asch, I believe the director would've placed Natalia more in the spotlight. But Natalia is placed in the background with the other characters, suggesting her importance is equal to them. Also, Luke speaks of the promise in response to Tear asking him why he's there. The promise he made to her was to return home. Finally, "Luke"'s physical appearance is in favour of Luke, which the director monopolises with a choice shot of "Luke"'s sword. The only thing working against this conclusion is "Luke"'s long hair.
Which, of course, leaves significant room for doubt. However, a few clues help to elliminate that doubt:
Coming of Age Natalia speaks of Luke's coming of age ceremony. Given that this is a Japanese game, and in in Japan a person comes of age when he or she turns 20, it may be true for this game. At the start of the game, Luke is 17. Although it's hard to tell, I think we can safely assume that the story's events took place over close to a year's time; he should be no more than 18 by the end of the game. That could allow for a two year gap, between Lorelei's release and "Luke"'s return. During this time, it's possible his hair could have grown out again.
Who Absorbed Who In the end, Luke emerged strongest between he and Asch. If it is Luke who's returned, it would suggest that Luke absorbed Asch, instead of the other way around like it was for the cheagle. Even if only a short time had gone by, Luke could have adopted Asch's long hair through this process. Although this can't be proven, it can't be disproven either. As far as I know.
In the end, I'm still unsure who "Luke" is. It's possible that the game developers purposely left his identity open-ended, never to be decisively solved. However, I could have missed something. If you have any insights, ideas or evidence you'd like to share, feel free to send me an email.
Otherwise, I prefer to believe that Luke returned to Tear and together they lived happily ever after.
I'm the same person who sent a review about Yukana. XD Anyway, I DO think Luke as in Luke Fon Fabre not Asch returned to Tear. It's clearly stated (for me) that Asch liked Natalia, Luke liked Tear, in clearance, Luke would've been returned to Natalia instead of Tear, if he's Asch. though also a proof is, all along the story, it was said that after being cloned, the replicas are more powerful than the original. There goes our proof. LxT still prevails.