Irredeemable #1 (2009)

Written by Mark Waid. Art by Peter Krause. Cover by John Cassaday. The Plutonian was the mightiest hero on Earth. Alongside the planet's other heroes, he worked to keep the world safe. But something has happened. The Plutonian has gone on a murderous rampage, killing his partner Samsara as well as others.  The heroes who were once his allies gather to try to unravel his mysteries: what his name is, where he came from, and how his powers work. And they need to do it quickly because he's hunting them.  Irredeemable asks the question: what if the world's greatest hero decided to become the world's greatest villain?  

Key book; premiere issue. Many other issues are available.  With a special afterword by Grant Morrison.  Near mint condition