These armies of darkness were once in the service of the legendary dark lords Varexes and Baltasar, but although many still serve the will of their late masters, many also serve Ix, the true god of death, or any sufficiently corrupted and evil high priests who have recruited them into their fiendish cults. They have been a scourge even since before the Cataclysm; indeed their masters’ lust for power was, in part, the cause of it all; and they have terrified, conquered and destroyed many a kingdom in their ghastly greed.
The Dark Legion starter deck army is Powers of Darkness.
Dark Legion is focused around methodically developing ways to continuously reinforce themselves as well as taking advantage of the carnage of battle that always occurs. Lysis is great for snagging the big creature that threatens to obliterate your dark army. Crypt Doctor can recycle creatures that are dying into health for other creatures. Carrion Feeder grows stronger with ever meal it has (and of course, guess what it's favorite food is). Gather Spirits, Altar of Ix, Planar Rift, and Nefarious Research are all designed in some way to take advantage of quick creature creation and dying creatures. Need some quick reinforcements? Don't worry, Zombies can spawn in any area you control, and Journeyman Necromancer can turn any corpse he sees into a Zombie, allowing easy reinforcement in numbers. The Duchess of Dunmar can also turn defeated enemies into Bloodlings, provided she had a bite on the target. Red Imps can teleport everywhere and be a nuisance, while Fire Beetle and Demonic Surge use alternate methods of dealing damage. Legs of Baba Yaga makes it easy for DL to grab a flux well provided they have a building to use it on. Stalking Spirit regenerates upon death, which makes it near invincible unless it's spawn point is blocked off. Nether Plasma is the "Swiss Army Knife" of DL, serving purposes from being an easy lab rat for sacrifices to blocking enemies of in choke-points.
Dark Legion is infamous for it's ability to "steal" and revive creatures, and you, dark one, shall be no exception. Utilize Possession and sacrifice the Possessed creature in one of many ways, then Reanimate the corpse to make a worthwhile soldier or use Claimed. If you have a liking for Vampires, and all your worthy broods have died out, play a Belfry of the Restless and they'll be as good as new given a few turns.
Early Game, you can chose to rush with Hell Cats, Red Imps, and other weenies, but a wiser player is better off saving for domain level 2. You may have access to tempting cards like Demonic Surge, but save it because you will need it.
Mid Game, with 2 domain levels, you'll now be able to fully take advantage of your powers. Get your minions into battle aggressively, as you can take advantage of their deaths to gain flux (Altar of Ix, Gather Spirits), draw cards (Nefarious Research), heal others (Crypt Doctor), and augment your power (Carrion Feeder, Stomachless Ghoul, and countless other cards). Legs of Baba Yaga is a great card to use if you haven't got a second flux well already; with another building, you soon will. Oh, and if your scout got killed in enemy territory, good for you! Transform his corpse into Corrupting Flux, and watch your opponent's buildings wither away.
Late Game may almost seem like gravy, but in reality, sometimes it's what wins DL players the game. With the ability to take advantage of enemy corpses through clever use of Reanimate, Claimed with Blood, Possession, Tortured Ghost, and Death Mark, you will be very hard to stop and most likely win because of powerful creatures like Barbed Necrath.
Happy Hunting, new Dark Lord.
NEVER, NEVER let DL players get 3 domains with 2 DL levels. This is the requirement for many of their best cards, and the process is actually much easier than it looks. Try to limit the amount of corpses that appear on the battlefield, and keep in mind that DL cannot deal with enchantments, so play powerful enchants like Piked Heads and Desolation Totem to stop them. Heal your dying creatures, and always have anti-enchants ready if your enemy reaches domain level 3 with 2 DL domains. Make powerful buildings like Belfry of the Restless and Altar of Ix major targets. And don't assume you've won if a Journeyman Necromancer or Duchess of Dunmar is still standing, because there might be a new army swarming up in a few turns. Keep in mind some of the more dangerous DL cards still have weaknesses. After all, what's a Putrid Zombie when it blows up at it's own base?