Overlord, Vol. 13 (light novel)

"An army forty thousand strong is clamoring at the gates for human blood, and there is little hope of reinforcements. The Sacred Kingdom's strongest paladin, Remedios, leads the defense of the city, but even she cannot stem the tide on her own. Despite the dire circumstances, the unimaginably powerful King of Darkness has refused to lend a hand for fear of depleting his magical energy right when he needs it to defeat Jaldabaoth once and for all. Time is running out for the defenders if they can't figure out a way to survive on their own"--Dust jacket flap.