Pluto

From Viz:
In an ideal world where man and robots coexist, someone or something has destroyed the powerful Swiss robot Mont Blanc. Elsewhere a key figure in a robot rights group is murdered. The two incidents appear to be unrelated except for one very conspicuous clue - the bodies of both victims have been fashioned into some sort of bizarre collage complete with makeshift horns placed by the victims' heads. Interpol assigns robot detective Gesicht to this most strange and complex case - and he eventually discovers that he too, as one of the seven great robots of the world, is one of the targets.

A remake of the The Greatest Robot on Earth arc from Astro Boy.

Note: Won the Tezuka Osamu Cultural Prize and the Excellence Prize at Japan Media Arts Festival in 2005, the Seiun Award for Best Comic, the Best Series at Italy's Lucca Comics Awards and the Prix Asie-ACBD in 2010 and the Intergenerational Award at the Angoulême International Comics Festival in 2011.
Was nominated for the Harvey Award in the Best American Edition of Foreign Material category and for Best Limited Series or Story Arc and Best U.S. Edition of International Material - Asia at the Eisner Awards and Urasawa was nominated for the Best Writer/Artist award for both Pluto and 20th Century Boys in 2010.