It Seems High School Prodigies Have It Easy Even In Another World! - S1.E12

Gustave is alive. All this time, he was hiding as Tanganika. In his fury, Gustave kills Conrad for destroying his golden statue. He then turns his attention to Jeanne and Shinobu, who were hiding in the same room. With all his might, Gustave destroys the castle killing everyone inside. Luckily Jeanne and Shinobu manage to escape.