This deck is focused around getting materials for ritual summoning and then with almost the same material you use MoC's effect to destroy opponent's cards.
Your main boss monster is Magician of Chaos, but you can also bring out Chaos MAX Dragon or Magician of Black Chaos MAX
This deck doesn't use Dragoon because I dislike that card even though it would probably make this deck a bit stronger. Besides, the main focus isn't on the Extra Deck
Your main way to summon your ritual (and some fusion monsters) is by using Secrets of Dark Magic which you can search with Magician's Rod. You can also use classic ritual support (Manju, Impcantation, Preperation of Rites etc.) need to get what you need.
With Eternal Soul you can revive DM or CoM, after it is destroyed or tributed
If you activate CoM's effect on opponent's turn you can destroy Artifact Scythe to prevent your opponent from using the Extra Deck
Extra Deck is made out of generic DM and not-DM cards which you can bring out relatively easy considering that the Extra Deck isn't that important for the deck (besides maybe Dark Magicians and Ebon Illusion). So don't worry about Extravigance. But I did add Quintet and Magicalized Fusion to flex on people :)