Maranatha is a creature of pure rage and destruction, similar to Doomsday but magical in nature. Whether or not he is indeed the manifestation of God's wrath apparently makes no difference, for it is real and is rage incarnate. He was defeated and captured many times in history, always managing to find a way back. In 1668 he was captured for good, and moved through various holding places until thirty years ago, when Julian Parker, Rabbi Sinnowitz, Mark Merlin, and Sargon the Sorcerer locked him away in the Prison of Industry. Five years later the Church assumed control of the Prison, but no mention was made of Maranatha all those years. What had happened was, Roland Finch positioned himself as a staff member in the prison, and trapped him inside the missing space that James Church once occupied before his Hyde side killed the original persona. This kept Maranatha trapped and hidden until he had Annie Palmer free James Church with the intention of having Maranatha kill her. After an exhaustive battle, he was defeated by the combined efforts of Catholic Girl, Rabbi Sinnowitz, Nun of the Above, Nun the Less, Julian Parker, and Xombi.
Maranatha is essentially unstoppable, a beast of pure destruction and mindless rage. However, the toll of multiple imprisonments and 3 decades of lurking inside the shell of a former man took its toll on him. Unlike Doomsday, Maranatha is capable of a degree of rational thought. He is perplexed by David's inability to die, and subsequently by his ability to be harmed. When he realizes that nobody fears him any longer, he loses any desire to go out fighting. In his final moments, he is asked by David if he ever had a friend in his life. Maranatha seemed confused by the question itself, stating "No. Any living thing I came across, I killed. That's all I was for. Rage powered my very being. It's what I am." Thus David concludes that he was never truly 'alive' at all.
A side effect of Maranatha's presence is echoes of the dead appearing in the vicinity. Nobody knows what they want, as they never spoke to anyone. The one exception to this was when David lay 'dying' from having Maranatha bite off nearly a third of his body. One of the spirits kneeled next to him and relayed it's laments that life is wasted on the living, and that the things they miss most are the most simple, such as the smell of dew. These echoes are apparently capable of interacting with physical matter, as one is seen handing David the Screaming Cannon left behind by a freshly killed Rustling Husk.
It is possible that Maranatha is still alive somewhere, as we have never been told where the Screaming Cannons teleport matter to.