According to Oda in a discussion with Mayumi Tanaka, Luffy’s voice actress, “no matter who joins, he always wants Usopp to be the weakest” since it would upset the balance of the story. Oda also states that this is because Usopp is the only one in the entire crew who is the closest in strength as compared to a regular human.

Since early in the series, he has struggled to match the physical feats of the stronger characters and needed his weapons or ammunition to take out foes.

He used to be a huge coward and often wanted to run away immediately, a trait he still carries to a lesser extent after his two years of training. This, coupled with him getting easily distracted or confused in battle have often made him less effective than his real potential as a sniper. So far, he appears to have moved past this after his training and takes better advantage of his wit and strategy.

Usopp’s character for a long time has been about going to Elbaf and living up to the story of the giants who he’s met from there.

Elbaf has had a prince named Loki, and Usopp’s most recent epithet is God. To throw some more fuel on the fire, he traditionally brings around a joke hammer to shock people out of commission.

I’ve seen a post that says that Usopp is going to make a Mjolnir when he gets to Elbaf, but that ain’t it. I’m calling it already, Mjolnir will be some royal treasure in Elbaf that no giant can pick up because it’s too small for giant fingers, with the added myth that only the worthy can pick it up.

Usopp’s gonna be the one to pick it up and the giants are gonna start worshipping him. It will not be effective in combat whatsoever, it’ll just be a new gag weapon that leads to people calling him worthy of the title “God.” It’s so goddamn stupid that I think it’s gonna happen.