okay but you gotta acknowledge that the first incineration Fig witnessed was within like minutes of them joining the team
i imagine that one in particular left a lasting impact on them in terms of setting the tone for their time in blaseball and maybe inspiring them to be the one taco to learn how to eat flame? so fig has eaten more flame because they have a sort of determination to do so based on their introduction to the splort
meanwhile Fish has witnessed so much incinerations that they were defenseless against, and despite appearing outwardly tough they still have a deep-seated fear of the rogue umps and, while having the skills to eat flame, it's still deeply painful for them physically and mentally to do so (I know some headcanons including my own imply that eating flame leaves a permanent mark on their body) and they can't bring themself to approach as often, which compounds that sort of "I could have prevented this" feeling.
It's made even worse because all but three of the incinerations Fish witnessed were due to Instability, so seeing the mark of instability on a player brings back lots of horrible memories for them... Then here comes Fig, who wears the mark proudly as almost a mark of pride rather than one of death as they confidently block countless rogue umpire fireballs. Imagine what that's gotta feel like for Fish, who watched two of their former teams get decimated by Instability in season 7 and then watched two more teammates get killed by it in the season before they came to the Tacos, only to see the Tacos' fire eater brushing away the consequences of the mark like it's nothing
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