Their lore is based on an alternative timeline where she was born to Beastclan lovers thousands(?) of years after dragons supposedly went extinct.

Realistically, she's matured (in lore) but is unable to grow due to a mutation formed in the embryo from being bound in their egg for many many years.

They're accompanied by:
Wellian & Thavis

Abyss Wanderer

Familiar

Deep-sea Maren wear enchanted fossils that allow them to traverse the upper reaches of the sea without the difference in pressure affecting them.

500

Windcarve Fugitive

Familiar

Some harpies prefer solitude to the cacophony of the cities of large harpy flocks.

2650

Seiche was found in a fossilized egg frozen in time, void of any warmth whatsoever, at the bottom of the cold and dark sea. Their egg was found by a curious archeologist Maren, named Wellian. He scooped up the egg, fascinated by the beautiful crystallized formations and the lack of any wear on the sphere. Not entirely sure what this belonged to, he brought it up to the surface, where his partner stood on a makeshift raft in the middle of the sea. He knew that Thavis knew a lot more about eggs and the incubation of them, but neither had seen an egg this large before. . .