Barron and Kaius have no backstory so that I can roleplay with them across multiple potential settings without it feeling off.
Although I do have furry characters constrained to stories.
Krro'Gaath, for example, is the dragon warlord of the Stonis Confederacy, which has successfully conquered the entire world of Stonis. He and his ancestors before him spent lifetimes in their conquest.
Krro'Gaath was the final warlord to take over before finishing the world-wide unification under his totalitarian rule. The one before him was his father, Garesh. Garesh was one of the most uninspired and weakest of the ancestors, according to Krro'Gaath, wasting precious resources on useless projects and himself rather than conquest, and the inefficiencies made Krro'Gaath furious. Krro'Gaath challenged Garesh to a duel for the throne. Garesh defeated Krro'Gaath, and as punishment, clipped off the wings of his son, leaving only boney stubs in its place.
Years later, Krro'Gaath watched as his future empire slowly decayed from neglect. Krro'Gaath had to challenge Garesh, but not before he took care of his younger brother, Voa'Des, as to not have any competition for the throne. Krro'Gaath killed Voa'Des and challenged Garesh once more, this time winning, and as punishment Garesh had his eyes gouged out and chained in a dungeon until Krro'Gaath decided he should die.
Krro'Gaath sought to unify and revive the dying empire, but the damage was already done.
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I created this backstory to make a character in a larger story. I made it up as I went along. He isn't based on me. He's closely based on Caesar from New Vegas, in so far as his temperament and attitude goes.