I think you are probably
Dante Alighieri, author of the poem commonly known as the "Divine Comedy" and more specifically of its first part, the Inferno, describing hell.
Aeneas was my forerunner, and I influenced Doom;
Not quite sure why Aeneas rather than Virgil (author of the Aeneid), who is Dante's guide through hell. One portion of Doom is actually called Inferno and has the protagonist exploring hell.
Many a man have I condemned, I’m both elegant and crude;
The Inferno is full of Dante's political enemies. Dante's poetry is generally considered some of the finest ever written, but many of the punishments he has the inhabitants of hell subjected to are pretty coarse.
I delve through burning wickedness, to the dark and frozen liar;
The burning wickedness of hell -- at the bottom and centre of which, in the Ninth Circle, is a frozen lake, in the centre of which is Satan himself ("the dark and frozen liar").
And I climb the mount of suffering, to reach Jehovah’s fire.
After making his way through hell, the second book of the Comedy ("Purgatorio") has Dante climbing a mountain on which Purgatory is located, to reach heaven ("Paradiso") for the third book.