Bhagavad Gita, Chapter 10, Verse 31

Of purifiers I am the wind, Râma of warriors am I; of fishes I am the shark, of streams I am Jâhnavi (the Ganges).

Strength used only for real good, never for harm, is what earns Ram his place on this list.

Being a perfect warrior isn't celebrated here for raw power alone, it's tied specifically to how that power was actually used. Real restraint alongside real capability is what's honored.