Apollo looked angry at the man while digging through his pockets for something. "No, seriously! I wrote the book-Pamphlet on how to kill demons! I know what I'm talking about!" He said grabbing out a pamhplet from his pants, and shoving it in The Doctor's face.
The first thing he was to see was the words "Are you a bad enough Dude/ette to help Doomguy fight demons!" with the cover of a beautifully hand drawn, and painted depiction of... Doomguy shoving a chainsaw straight through an imp, and out the other side with multiple demons attempting to attack him from all sides.
If The Doctor was to open it he would find the first section titled "You must fight the demons!:" Giving instructions on a work-out plan to keep your body in shape, some of the best weapons to get, incredible strategies for a number of demons, how to identify a demon, and the best way to loot a dead body.
This went on for about two pages before switching to a page titled "How bad was Doomguy! A 12/10 on the scale of badness!" that listed the incredible feats of Doomguy, introducing some parable-like nature to his story. Citing the three Ds, the main tenets of his faith. Duty, Devotion, and Doom. Duty being the obvious one in that Doomguy bravely chose to go back to fight the demons! Devotion being how one must devote himself to anything he does, which lead to Doom! Never giving up hope despite the giant demons, and what may be utter DOOM!! And also that one must not look upon death as a sad thing, but instead as fuel to greater encourage one to even greater deeds. Stating the parable of Daisy, the pet bunny(Showing a picture that was in memory of her) along with the parable of "I'M RADIOACTIVE! THAT CAN'T BE GOOD!" A sad parable about the state of the world, and walking through lakes of nuclear waste.
The next section was titled "Possession and YOUUUUUUUUUU!" and stating how sins make you more susceptible to the demons, and how you can avoid them. It said most of the usual things, don't kill innocents, be a nice guy, and generally be chariatable.
The very back was titled "WOULD YOU LIKE TO LOOK AT MY CANON!" and stating how no retelling of the parable of Space Marine Vs Hell Demons(Four games, expansions, and RPGs, A comic, six novels, a boardgame, and an early draft of the first game), it said that all are canon in a degree, but likely that the first two games are the most canon, and one should consider the others as a retelling from different perspectives, and went on for a while about it.
.... It was quite an impressive pamphlet, and was edging into the territory of Novella.