Hiei solos the HST at that point...
@GeneralVan: The Jinchuriki in Naruto would have the destructive capacity and durability to compete with Hiei, especially the Juubi. A combined Jinchuriki assault would be too much for the Jaganshi to handle all at once. Let's not also forget about Logia users from One Piece as well, who would give Hiei fits if he resorts to his regular attack methods outside of using Darkness Flame attack variants.
Current Obito is basically indestructible and possibly nigh-immortal with the Juubi, he's probably like Aizen with the Hyogoku except ten times more powerful in terms of destructive capacity. Plus, Obito basically blitzed and destroyed Hashirama and Tobirama at the same time without any effort.
@5th: Hiei is country level+ in DC and Durability and Massively Hypersonic+ in speed. Aside from the Juubi and Obito, no one is competing with Hiei. As for this battle if it was Dark Tournament it would be a close fight, but any incarnation of Hiei above that rips Aizen a new one. If Aizen regenerates, he gets ripped a new one again and Hiei kills him with ease.
For the last time, Aizen isn't immortal.
As for the match, Hiei wins it easily.
As for soloing the HST, don't see it happening. But he'd rack up a good-sized body count before his demise.
What proof do you have that he isn't immortal? As far as shown he is virtually unkillable, and was even said by c46 that he'd be executed if it weren't for him being immortal.
@solesamurai: And what proof do you have outside of character statements?
Even then, it wouldn't be the "perfect" or"godhood/ deity protection" kind considering immortality only implies he won't die naturally. Aizen can still be dispatched by a foe with the destructive capacity to completely wipe him and the Hougyoku out before the latter regenerates his body, which Hiei can do.
Saying that any foe, regardless of destructive capacity, can't kill him because "lol, he is immortal" is a no limits fallacy.