10 Times Constantine Outsmarted Everyone
2. Tricked Doctor Fate To Death - Constantine: Future's End
The first rule when dealing with John Constantine: it doesn't matter how powerful you are, if you give the man an inch, he'll take you to Hell.
Which is what Nabu, the spirit of the helmet of Doctor Fate, learned when he forced John to put on the helmet in the hopes of making him the new Doctor Fate. However, Constantine thinks fast and traps them in an astral plane spell known as the audience of Anubis. There, he challenges Fate to a game, where he has to prove to John whether or not he has ever truly given a damn about anyone other than himself.
Despite Nabu's claims that he does, having saved thousands of lives and thwarted the machinations of great evil, john brings up as a counter all the people he summoned to be potential helmet wearers, and then brings up Khalid, who was currently in Hell. Anubis, acting as judge, declares John the winner of the argument and "kills" Nabu.
Turns out though, it was all a trick. There was no Anubis, just an elaborate illusion, with some demons summoned to be on hand to really sell the fantasy. But that doesn't matter, Nabu accepted the terms of the challenge, and he accepted his "death". So John gets to take the helmet off.