Konosuba - God's Blessing on This Wonderful World! Vol 16

From the Yen Press edition

Megumin and Yunyun are shocked to learn of the dark god Wolbach’s appearance in the capital. But Megumin has a confession to make—she has broken Wolbach’s seal before, and she knows for a fact that the deity couldn’t possibly be there…But if that’s the case, just who could this impostor be? With more questions than answers, there’s only one way to find out—it’s off to the capital for Kazuma and friends!

Source: Yen Press