those are flags on the back of him.

Flags, like Yoshimitsu from Tekken and Soul Caliber, only Hotaru has 2.

LOL LOL LOL I don't know but they look really cool. I like them, flags, whatever they are. They did sooo much better on designs and making fighters look like their poised to kick but this time around. EXCELLENT!!!

Those flags are part of the Japanese colture.
Samurai's wore them in battle representing their clans, or themselves... they also wore them so that generals can notice their position in large scale battles where everyone looked the same.

Something like that...

Yes, that flags represents the clan( the clan ́s crest was on them) and the generals or high ranks samurai often wore them..
prety much like the guy above me says

I, personally, dislike the flags. Hopefully, an alternate outfit of Hotaru will not feature these. Too large & distracting.

*SGO* Wrote: Yes, that flags represents the clan( the clan ́s crest was on them) and the generals or high ranks samurai often wore them.. prety much like the guy above me says

This is correct.
If you want to see this in action. I suggest you watch the final battle in The Last Samurai. Damn that's a good movie.