Headcanon: Aethea doesn't just like fire, she gets mesmerized by it, similar to what happens to her in her hyperfocus, she can sometimes end up staring at something until it burns out completely, and when she's not looking at the flame she doesn't completely understand why she is so drawn to it. Maybe, she theorizes based on vague leftover feelings, she sees what happened during her creation, maybe in the glow of the fire she sees memories of the past, of her old home, maybe it's something completely different. Regardless she's fascinated by it, and can never stay away.
Hope you like it~
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I love that headcanon, that's accepted as canon