The Great Evil Beast

This story opens with Cain and Abel who from a safe perch can watch the battle between good and evil begin.John Constantine puts Swamp Thing into the position where he can help stop this, in a two-front battle.Swamp Thing and a host of notable  magic users (like Phantom Stranger,Dr. Fate ,Deadman andEtrigan the Demon - who is leading an army of demons who don’t WANT the status quo to change) into battle with the Soul of Darkness .  Fate encounters the evil tricksters

   The Demons Three , (Abnegazar, Rath, and Ghast) who are all too happy to help this Evil take over everything.Before the battle officially starts, the Demons Three warn Fate of the rules. Fate doesn't give them the answer they thought they'd get:as he kills  Abnegazar .

Meanwhile, back on Earth, Constantine leads a group of the most notable magicians (Mento, Zatara, Sargon,Zatanna,and Madame Xanadu ) to  stop it. In the ensuing magic battle, both Sargon the Sorceror and Zatara are killed.

 Ultimately, it all comes down to Swamp Thing

(as Constantine planned it), who convinces the Soul of Darkness that evil and good are not necessarily at odds with each other - the Shadow then strikes up a balance with the Light of Heaven, and all is right with the world (except for the casualties, of course).
Also Cain can`t help himself killing his brother one more time.