(1140) Theory on Usopp and Loki
It's theorized, that King Harald was alligning himself with the World Government in a shady deal, and Loki put the stop to this. I have a feeling, this will be a parallel to Usopp's backstory and journey.
Both started as a liars and troublemakers, who gave nothing but trouble to their respective communities. Loki the God of Mischief, God Usopp the liar. Both nothing but troubled youth, misbehaving and lying.
Then one day, they discovere a horrible plot. Usopp finds about pirates coming to invade his island, Loki finds about his father selling their Kingdom's loyalty (and propably their heirloom) to WG. And when they tell about this, no-one believes this. A boy crying wolf.
So they both decide to deal with the problem themselves, and take the blame. Usopp doesn't reveal the truth, instead letting people believe he truly is a liar, and nothing bad happened. Loki also takes the blame, letting everyone think he is not just a liar, but a kingslayer. And even when he gets captured and locked up by Shanks, he won't tell the truth, because the truth would just hurt everyone.
Due to these similarities, I believe Loki and Usopp will have meaningful interractions in the future. Usopp's dream of becoming a great warrior of the sea has always been very much inspired by Elbaph warriors, Loki can expand that image, even challenge it. And if Loki sees himself in Usopp, who knows, power up could always be nice.