I just finished a re-read of 'Fort of Apocalypse', so this is fresh in my mind. The ending feels like a proper conclusion, but leaves a few threads that could spin off. The core group finally manages to secure the school grounds after that insane final battle, establishing a relatively stable safe zone. Yoshioka's leadership gets solidified, but not in a cliche 'king' way—more like a weary, pragmatic acceptance.
The real kicker for me was the fate of Kurusu. After all that internal conflict and moral wrestling, his sacrifice to buy time for the others to fall back to the fort was brutal but fitting. It closed his arc of seeking redemption perfectly, but man, it hurt. The last few panels show the group looking out from the walls, not celebrating, just exhausted and watching the horizon. It’s a quiet, somber victory, which fits the series' tone much better than a fireworks display.