Pluto. Urasawa x Tezuka. Volume 7: Naoki Urasawa

Who Killed Astro Boy?
In an ideal world where man and robots coexist, someone or something is after the seven great robots of the world. Interpol assigns robot detective Gesicht to this most strange and complex case--and he eventually discovers that he is one of the targets!
Pluto has destroyed six out of the seven great robots of the world, and the pacifist robot Epsilon is the only one that remains. Will Epsilon, who refused to participate in the 39th Central Asian War, leave behind his war-orphaned charges to step onto the battlefield? It just might be that kindly Epsilon, who wields the limitless power of photon energy, will be Pluto's greatest opponent of all!