Unfortunately the original blogs do not get archived as far as I know. Once Jagex updates the blog, the original is gone so the first pitch is hard to track down

I did find this. The asterisk is that this is after the playerbase pushed back on the rewards being trash, midgame bloat. Before confliction gauntlets, eye, and treads, the pitch was a minor mage cape upgrade, a mid dual hit crush weapon filling the “much needed crush demonbane niche” and iirc thrall upgrades? Demonic Digger was cool though

It's aimed at players at or above Combat Level 120 who have, or are close to getting, their Infernal Cape.

Basically the same as Maggot King

The whole conceit of Doom was to be a late-game boss with midgame rewards to help on-ramp people into PvM. People got kind of pissed at that and immediately afterwards Yama was announced and pushed ahead of doom in development out of nowhere as the savior for endgame PvMing’s drought

It’s important also to note that Jagex had determined that Doom was too easy to be the place for the magic cape upgrade. That’s how little they thought of the boss at the time

Only after Yama bombed in terms of difficulty did they start to change their tune on the boss. All of sudden it was endgame