Also, should specify F2P; I have other 5*'s I would rather focus on.
Seems like Klein is actually the best choice, with a decent speed stat and a PRF brave bow. Build with swift sparrow or A/S solo and you have a monster. Throw in a lull and boom (or desperation, if the map calls for it).
Additional info: you can consider the unit at 5* +10, but maybe not with full flowers (though that is unlikely to make a difference); flowers are just in too high demand, even if I want to get around to it eventually.
Alright, show me them archers.