In the LIGHTNING RETURNS: FINAL FANTASY XIII Ultimania, Director Motomu Toriyama explained why they went with Hope’s form from FINAL FANTASY XIII in LIGHTNING RETURNS: FINAL FANTASY XIII and shared his personal feelings about Lightning being in a relationship. You can read it below thanks to The Garden of Everything.
– Is there a specific reason why only Hope appears in his FFXIII form?
Toriyama: We had a lot of trouble trying to decide whether Hope would appear in his FFXIII or FFXIII-2 form. Ultimately, because this is the final installment in the trilogy and because we felt that it was important to acknowledge the fans, we went with the popular younger appearance for Hope. At the same time, I also wanted to progress the relationship between Hope and Lightning a little more from what it was in the first game. And of course, with the story reaching a conclusion, I felt it was important for their relationship to also reach a climax of its own. Considering all this, we directed the scene where Hope appears in his true form as though it were a real farewell. But personally, I don’t want Lightning to belong to anyone, and I also like to think that she only relaxes around Odin. LOL