Whether You Call Me a Guardian Dragon or Not, I'm Going to Sleep - Chapter 6: Age of Dragons (1)

... ed their pectoral fins as front legs.

Driven by the fierce competition for survival in the water, these creatures fled to the surface.

Initially, they evolved to escape to the water's surface during emergencies.

Then, perhaps realizing that life above water was better than expected, they began to evolve lungs instead of gills and transformed the fins behind their gills into front legs.

Truly, I had made them capable of mutation and evolution, but seeing them devel ...