[PreSage]

Originally Posted by kuromitsu

I think Shino is a boy, but he's also connected to the princess? Somehow? Also, it seems princess was in fact a cross-dressing boy because Kakihara Tetsuya did her narration... But Shino must be one of the dog warriors as well, since his name has the kanji for "dog" in it (Inuzuka Shino).

Btw, I'm not very familiar with the original Hakkenden story, but afaik the setup goes like this:

Spoiler for just to be safe:

A clan is under attack, and the lord swears to marry his daughter (the "princess") to whoever kills the enemy leader and brings him his head. So when his dog happens to be the one to kill the guy, the princess decides to bite the bullet and go live with the dog someplace away. Somewhere along the line some union occurs on a spiritual level, because they're both so virtuous and stuff? I think? The clan is eventually defeated anyway, so a retainer tries to escape with the princess. He ends up having to kill the dog but he accidentally kills the princess as well. Her juzu beads (each standing for a virtue) scatter and each gets attached to a baby - these will eventually grow up to be the eponymous eight "dogs," sons of the princess and the dog (somehow), who will attempt to resurrect the clan. They all have the kanji for "dog" in their name.

There's also an evil ghost involved, a woman who was involved with the enemy leader(s?). She was killed by the princess' dad and her ghost continues to haunt his clan.

Going by this, and assuming the mangaka applied some poetic license in her manga,

Spoiler for speculation:

Shino is the reincarnation of the princess, but also one of the dog babies. Somehow. Or maybe he's not a reincarnation but has her soul inside him or something, like the fox guys said? We see him with some princess-like woman in the OP so I guess there must be some connection there. Sousuke is obviously the dog the princess married (ooh I see the main pairing now). We see the other dog guys in the OP.

ETA:
I just looked up the original story and woooh boy. o_____o) (It sounds pretty awesome, though.)

About Shino, that's what I'm thinking now, too, but your explanation and the extra info on the Hakkenden story made things a lot clearer. Thanks.