I see your confusion with its name having -ion at the end; that comes from Champion, not Lion. Also, it's based on a takin, or a "goat-antelope" (again, no lions here).
Terrakion is derived from terra (Latin for earth), or terracotta (a clay-based material, as well as its respective color), and possibly takin or champion.
The takin, also called cattle chamois or gnu goat, is a goat-antelope found in the eastern Himalayas.