Extus Danger [[PRIMER]] (EDH / Commander)

This is a proactive midrange combo deck that wins by casting an infinite mana line, then resolving Awaken the Blood Avatar until the table is dead. The deck leverages Extus' recursion on value creatures with spellslinging engines to loot through the deck to find any of the combo lines, which include:

~Auriok Salvagers + Lion's Eye Diamond
~Chain of Smog + Storm-Kiln Artist
~Worthy Cause + Dockside Extortionist (4 treasures)
~Cloudstone Curio + Dockside Extortionist + 1cmc creature (4 treasures)
~Underworld Breach + Stitcher's Supplier + Culling the Weak
~Underworld Breach + Grinding Station + mana positive rock (Mana Crypt, Sol Ring, LED)

Gameplan - Our primary engines for getting one of these combos are Past in Flames, Ad Nauseam, and Mizzix's Mastery, which give us the power to loot through nearly our entire deck. Loot spells should be used liberally, discarding any creatures from our hand to look for our value pieces. Because most of the creatures in the deck are incremental value pieces as well, the option to play or bin them gives this list a surprising level of resilience.

Card Synergies -
An early Children of Korlis with Necropotence or Ad Nauseam can win the game remarkably fast.
Azra Oddsmaker draws 4 cards if Extus is the creature that connects.
Street Wraith is essentially "pay 2 life, draw a card" on every instant or sorcery cast while Extus is out.
Darkblast should be played as early as possible; Dredge 3 helps so much.

Convoluted Dockside line with Darkblast, as long as Extus is on the board, Ubreach in hand, and Darkblast/Village Rites/Dockside either in GY or hand for 2RRBB that can go infinite if Dockside generates at least 5 treasures. Cast Ubreach (1R), and if Dockside is in your hand, play it (1R). If Dockside is in the yard, cast Darkblast (B), triggering Extus and returning Dockside to hand, then play it. Create 5 treasures. Cast Village Rites (B), sacrificing Dockside and triggering Extus to return it to hand, then Dredge 3 off the draw to return Darkblast, feeding UBreach for Village Rites. Each loop once UBreach is down costs 1RBB so as long as you can make 5 treasures, this will go infinite and you can sac Extus with a billion treasures to end the loop with Village Rites, then cast Awaken the Blood Avatar as many times as you want.

Mulligans - An ideal hand has two lands, a ritual effect, a loot effect, interaction, and a mana positive rock. You can use rocks or rituals to get Extus out early and start running loot effects to fill the yard. The furthest you should mulligan is 5 unless you have something like a Christmasland hand of Dark Ritual, Command Tower, Mana Crypt, and Ad Nauseam for that sweet, sweet turn one Ad Naus.