In BFDI, Firey spent a good amount of time slapping Coiny. Firey can also be quite forgetful; e.g. him not realizing that lava can kill Leafy in Insectophobe's Nightmare 2, seemingly forgetting who Leafy is in "Get in the Van" and events afterward (though this is proven to be false). Though, by the end of Season 1, he seems to have developed more of a genuine understanding of his surroundings and interactions with the other characters, such as acknowledging his unintentional cruelty to Leafy and revealing his thoughts on the conflicts around him. He also displays signs of genuine sincerity, such as when he reveals his true feelings to Leafy about her.
However, from BFDIA onwards, Firey completely ignores Leafy and has a blank expression whenever nearby. The reason for this is explained in "The Four is Lava" when he tells Leafy that he didn't want to be associated with her because Leafy stole Dream Island. This paints him as somewhat selfish and uncaring, given how he's willing to lie about not knowing Leafy to save face. But doing this also seems logical on his end, given how Leafy stole Dream Island and committed other misdeeds, so if Firey were to "forget" Leafy, people wouldn't think poorly of him, and it could provide him a benefit in the competition.
Despite this, Firey still cares about Leafy and his distant behavior along with his actions in "Who Stole Donut's Diary?" were him being bitter about losing Dream Island even though he won BFDI. Eventually, Leafy was able to fully apologize to him and intentionally lose the challenge to make up for her actions, thus reconciling their friendship.
Firey is also rather dim-witted. In "Take the Tower", Gelatin (who was in disguise) was able to fool Firey to infiltrate his team's tower. He also believed that the real Flower was the impostor.
In Firey and Friends, Firey is more clever and more of a trickster to his rivals, while on other occasions he's trying to be help other people to make him more friendlier.
Battle For Dream Island Again Do-Over shows a far more sadistic side of him.
