Constantine (Renaissance), book 3: The Voice in the Fire
Ray Fawkes et Collectif2015

A MAZE OF MAGES

After a lifetime spent playing with fire, John Constantine has gotten himself well and truly burned.

The most infamous mage in the world thought he could take on the Cult of the Cold Flame, a cabal of sorcerers whose unspeakable powers are matched only by their fathomless evil. But he learned the hard way that he couldn't beat them. He could only join them.

Now, he's been sent into battle as cannon fodder by his new masters-a weapon aimed at the few mystics who have yet to bow to the Colf Flame. Win or lose, live or die, evil comes out on top.

Or will it? Constantine has a secret plan to unite the remaining rogue mages - and a hidden desire to do good, implanted in his old black heart by the love of his life. To pull it off, he must travel the world (and the worlds beyond it), but his deadliest journey may take place in his own tortured mind..."
(Collects CONSTANTINE #13-18)