Hai to gensó no Grimgar (japonsky 灰と幻想のグリムガル, Hai to gensó no Gurimugaru; v překladu Grimgar, svět popela a fantazie) je japonská série fantasy light novel spisovatele Ao Džúmondžiha, kterou ilustruje Eiri Širai.
After he witnesses his father’s murder at the family dojo, Ryo Hazuki dedicates his life to finding the man responsible — a mission that takes him from the streets of Yokosuka, Japan to the sprawling metropolis of Hong Kong, and beyond.