Dalton started out as one of King Wapol's guards, though he never agreed with how Wapol treated his people. He was even present when Wapol met with Vivi's father back in Alabasta. Everything changed when he witnessed Hiruluk's sacrifice—it inspired him to finally stand up to Wapol. For that, he got thrown in prison and spent his time being mocked by Wapol and his cronies Chess and Kuromarimo. When Blackbeard's attack forced Wapol to abandon Drum Island, Dalton stepped up and basically held the kingdom together by himself, earning the people's respect in the process.
The Straw Hats showed up looking for a doctor to save Nami, and Dalton was initially suspicious they were there to cause trouble. He pointed them toward Dr. Kureha, the island's only real physician (though she had a reputation as a witch). When Wapol came back and recaptured Dalton, the whole island—including the twenty best doctors—stuck by him. Wapol even seriously injured him while Dalton was protecting civilians from arrows. By that point Dalton was ready to blow the castle sky-high if it meant stopping him, but Luffy took care of it instead, launching Wapol off the island for good. The grateful people of Drum made Dalton their new king and renamed the place Sakura Kingdom after the pink snow that Hiruluk's special medicine had created.
He eats the Ushi Ushi no Mi, Model: Bison, letting him transform into a full bison or a human-bison hybrid form (basically a minotaur). The English anime calls it the Ox Ox Fruit instead.
Later on, he's shown sharing the Straw Hats' new bounties with Dr. Kureha, though he chooses to live in the village rather than in the castle.
Content compiled by AnimeList.moe from publicly available sources.
