Loki is viewed as a cursed prince and harbinger of destruction based on outdated customs and lies. Harald's life lesson was that the giants dont have to be destroyers, but creators and protectors. One of the biggest plot points in Elbaf is forcing the giants to be destroyers against their will, which is ironic, since in a way they forced Loki to be one.
Loki's views himself as Nika and the harbinger of destruction of the world, which shows how he falsely attributes Nika to destruction. Loki follows the same archetype as Wiper, Law, Momo etc, in which while they may be a protagonist, a chunk of their motives and actions is wrong, which is where Luffy comes in. Law for example thought he was fighting for his love of Corazon which in reality, it was hatred for Mingo, betreayed what Corazon wanted from him in the process.