I think Loki is being set up to be the whitebeard to Luffys Roger so i believe he'll continue to be important to the story after Elbaf especially when you consider the Harley scrolls illustrated a giant working along side humans
Once Loki finds out Luffy defeated Kaido, it will be real hatred
Once Zoro KILLS KAIDO? Hoooooooooooo baby, that's a blood war
Loki appears to be very like Luffy, but also very NOT LIKE Luffy, and, because of that, I think he ends up with Blackbeard: someone who is a lot like Luffy in a lot of ways, and the polar opposite in very important areas (ie, loyalty).
Personally, though, I want Loki to join Kidd. I think Kidd will surpass Loki sometime in Elbaph. Pirates typically unlock CoC after fighting strong opponents with it; Shanks Kamusari on Kidd is going to lead to Kidd unlocking his CoC.
Bonus points if Shanks trains him because Garling is the one who destroyed Kidd's homeland and "killed" Victoria (still on the Victoria is Gunko train)