This deck is an attempt to mimic the gameplan of Cubelock, adapted to the current meta by increasing speed, consistency, and highroll potential. Almost every card in this deck is a part of some broken highroll combo.
If this deck can hold its own against Seedlock and Odd Questline Hunter, it should be in a good position against the rest of the meta because no popular decks are great at dealing with big, sticky minions.
How is this more consistent than historical Demonlock decks?
The minion pool in this deck is extremely specific - even Kobold Librarians are intentionally excluded. Combine that with 7 total minion tutors through The Dark Portals Free Admissions, and Archwitch Willow and this deck is able to consistently draw all 9 minions by turn 8 or so. With such a focused minion pool, Raise Dead can easily be manipulated to almost always find Voidcaller and a big demon.
In addition, Runed Mithril Rod and Backfire allow this deck to keep a full hand of cards practically without sacrificing tempo, which supports the inclusion of the Sacrificial Pacts and the general effect of Voidcallers draining your hand. The discounts from the Rods additionally allow finishers like Archwitch Willow and N'Zoth, the Corruptor to come down on turns 6-8, which, unlike turn 10, are all real turns which currently exist.
How can this deck beat Seedlock or Odd Questline Hunter?
That I can tell you in one word - healing! This deck runs 24 base healing through Sacrificial Pact, Touch of the Nathrezim, and Drain Soul, and moving into turns 6+, Mo'arg Forgefiend and Enhanced Dreadlord take over. If Seedlock or Questline Hunter leave the big demons alive, you play Battleground Battlemaster and Power Overwhelmings and swing face for lethal. If they kill the big demons, you swing face with Desperate Dreadlords (optionally add Battleground Battlemaster), get enormous heals, and summon more healing demons. This tends to buy you the turn or two you need to assemble the Battleground Battlemaster/Power Overwhelmings to seal out the game.
If you start with none of these, search for Voidcaller.