Welcome to the Doomsday Wiki!
The Doomsday Wiki is intended to be the most complete and up to date work on how to cast the card named Doomsday in the Legacy format of Magic: the Gathering.
There is actually much more to how to play the deck, but understanding how to cast the namesake card of the deck is a pretty big piece of the puzzle. This is specifically not a primer as you often see for other decks in Legacy, because primers generally become outdated rather quickly and are more about card choices, decklists, sideboard plans, and so on. The Doomsday Wiki is there to help people to really understand how the deck works and can win in various scenarios.
We have three main variants represented on here that you can access resources for on the left hand sidebar.
Doomsday is the primary deck variant that is having previously unprecedented success since the printing of Thassa's Oracle. Legacy Doomsday uses countermagic like Force of Will and discard like Duress to play a controlling game before ending the game.
DDFT (Doomsday Fetchland Tendrils) is the closest to historical lists. Although it adopts the current usage of Thassa's Oracle these decks tend to also have access to secondary Storm plans using cards like Burning Wish, Echo of Eons and Tendrils of Agony. They also prefer proactive protection like discard over being able to run reactive countermagic.
Entombsday is a Tin Fins variant with a main deck plan focusing on reanimating Griselbrand using either Shallow Grave or Goryo's Vengeance to then have it attack alongside Emrakul, the Aeons Torn or looping the deck to generate infinite mana and hard cast Emrakul or cast Collective Brutality an infinite number of times. The key point to focus on is it runs a dedicated transformational sideboard into a variant of Doomsday.
If you are new to the archetype then check out the FAQs Appendix for any initial queries you might have. Peruse the Wiki, read some of the articles and come visit us in the Discord.