Fate / Zero Volume 4

More about the book

"Kiritsugu's ruthless mission to eliminate mages leads him and Maiya to bring down an entire skyscraper just to kill the residents of one floor--Kayneth and his servant, Lancer. But in the ruins, it's not their bodies that are found, but instead a mysterious spere...while elsewhere, the most depraved sorcerer of all, Caster, uses hostages to draw out the protective instincts of the noble Saber!"