Designer - "Yo Masuda check out these wicked designs, here's this awesome burly fire/fighting wrestling cat, this sneaky stealthy grass/dark sniper owl and I wanted the water seal to be fairy type so I just turned him into a girl!"
Masuda - "Sorry dude, I know its becoming a tradition but fans will throw a shitstorm if we have another fire/fighting starter. How about you make him fire/dark? just come up with some bullshit about how he fights dirty."
Designer - "B-but, the grass starter already has dark as a secondary type"
Masuda - "Hmmm... just switch it to ghost, uh, owls are kinda spooky... I guess."
Designer - "Done and done. Thanks senpai you're a genius, it's no wonder you're heading the pokemon franchise."