HAPPY BIRTHDAY, EMMY!
"Usopp's different when he puts that mask on."
No one paid the simple comment any mind or any really attention. Of course Usopp was different when he put on the mask and cape; some people needed something to hide behind in order to be their real self. In Usopp's case it was a lie that just happened to be a different version of the same truth. Luffy's crew smiled and told him of course Usopp was different with the mask, even if they didn't quite understand when Luffy told them he was different without the mask, too, sometimes.
Luffy gave up hoping any of them would understand. He knew that despite missing something rather obvious right in front of them, they at least had the important part of caring about Usopp done right. It was left up to Luffy to wrap his arms around Usopp one night when he smiled a different sort of smile under the moonlight and for Luffy said, "I love both of you."
After traveling with the Thousand Sunny and finding family in her crew, going back to visit Kaya no longer felt like going home. It was like returning to someone important, of course, but Usopp's heart was invested in new hopes and new dreams. Dreams he wanted to share and dreams he was delighted to find his friends and family sharing with her. She smiled and laughed at all their stories, eyes shining brightest during Usopp's.
He tried to pretend it was home for a while, saying goodbye to his new family and trying to find something of the old on a single island. Usopp's eyes kept drifting to the horizon when they weren't fixed on her smiling face and shining eyes. Those remained bright and firm in his mind like a guiding star to lead a ship back to port. One long day some many months after, his family returned. Usopp didn't want to leave them again, wanted to return to that place that felt like home. But that meant leaving his star behind as well. It was a choice that would haunt him no matter what he decided and he knew it was a goodbye that would last for ages no matter who he said it to.
It wasn't until later, when Usopp stood at the dock and watched the Sunny getting reloaded, that he saw Kaya approach with a smile and bright eyes and a heavy pack over her shoulder. She grinned at him and said, "So where are we going?"
"Home," Usopp said and caught her in a tight embrace.