I've just started reading this manga, and I think it's awesome so far (even though there's 9 chapters atm).

For those who aren't familiar with it, here's a synopsis:
Apocalypse no Toride, or "Fortress of the Apocalypse" by Kuraishi Yuu, follows 4 inmates at the Shouran Juvenile Reformatory: the falsely accused Maeda Yoshiaki, cool but dangerous Masafumi Yoshioka, the strong and silent but fair Iwakura Gou, and the smart-mouthed genius Yamnoi Mitsuru.
Upon arriving at Shouran on false murder convictions, Maeda Yoshiaki would rather be anywhere on earth, but when a van full of infected zombies crashes into the prison and begin to attack the guards and inmates, Maeda and his cellmates begin a fight to the death to stay alive amongst the infected from the outside world and the anarchy that arises within the prison.
Eventually forced to leave the prison's walls of safety , the boys of Cell 4 find horrors in the ravaged cities beyond what they could have ever imagined.

I love how the main characters aren't just a bunch of average people that suddenly become zombie-slaying badasses; these guys know how to kill and have no conscience about doing it!
It reminded me quite a bit of HOTD in terms of how the story progresses (they look for Maeda's parents, the prison becomes a stronghold which will no doubt be overrun soon, armored trucks). The art style is definitely similar to Shingeki no Kyojin, imo.

So, is anyone else following this series? If so, what do you think about it?
I'd definitely recommend it to anyone who likes a good horror/zombie series.