Re:ZERO -Starting Life in Another World-, Vol. 22 (light novel) — Tappei Nagatsuki

WHEN WILL THE EXAMS END?Subaru makes history with his friends after reaching the unreachable tower deep in an unpassable land that even Reinhard finds inhospitable. Waiting for them is a Sage who is quite different from all the stories...not to mention several tests set up centuries earlier to judge the worthiness of visitors seeking the untold knowledge resting within the tower. If they pass, access to the hidden wisdom of the legendary Sage may help them find a way to save Rem and the other victims of the Witch Cult. Fail...and they might not leave alive...