honestly what he's doing it's not very "shadow" other than the fact that it's mysterious, but I thought his intention was to be strong but don't show-off always (like, leave the showing off to the true protagonist and be almost underestimated) to get people off-guard or something
if he continues to appear in every fight to show off his powers then at some point it won't be such a surprise anymore, it'll be just expected of him, like a main protagonist