Strategy

The best way to use Necromancer is taking advantage of it putting a cheap body on the field every turn, treating that as virtual card advantage while you trade topdecks from a pile of the strongest Water spells in the game.

I'm not interested in doing that. I want to make skeletons to use them as skeletons instead of generic value. There are Earth sites and Air sites that make skeletons, so we're in Earth and Air. The plan is playing undead and smashing faces. Ideally, we buff their power past 1 just so they survive long enough to get in and attack, but it's possible to get the job done without an [[Eclipse]] or [[Death Knight]]. We end the game with a [[Bone Spear]] or a mass of skeletons and [[Witching Hour]]. We generally don't want the game to go super long, just because we get out-valued if we start trying to trade six-drops. There are a handful of ways to spend that much mana in here, but that's ultimately just because I like them.

Strengths

If you make enough skeleton tokens, they don't need to move to defend!
(Mostly) inexpensive minions without spending cards to make them make the deck pretty resilient against single-target removal!
Spooky, scary skeletons send shivers down your spine
Shrieking skulls will shock your soul, seal your doom tonight

Weaknesses

Skeleton tokens on their own can't attack a flipped [[Druid]], die to a [[Murder of Crows]] or [[Divine Lance]] or [[Abyssal Assault]] or [[Arid Desert]] or [[Briar Patch]] or [[Flayer]] or [[Rain of Arrows]] or [[Static Servant]], can make a [[Blasphemy]] DESTROY us...
There is some extremely strong removal targeted at Evil, so it's very possible for our [[Death Knight]]s to get banished

Card Packages

Ways To Make Skeletons

Our Avatar

[[Necromancer]] of course

Artifacts

[[Pile of Skulls]] has the additional benefit of being able to banish cards from our opponent's cemetery, and our recursion is basically limited to [[The Pallid Bust]], [[Carrionette]], or [[Skeleton Mage]] so as long as we're banishing Magics that aren't Ordinary it's all gravy.

Minions That Make More Minions

[[Noisome Twosome]] is effectively three power for two mana. Very solid.
[[Novice Necromancer]] comes with a buddy and the ludonarrative sense that our Avatar has apprentices is delightful to me.
[[Stygian Archers]] is three ranged power for three mana that ALSO summons skeletons when they kill. Exceptional, indeed.
[[Master Necromancer]] may not be quite on the level of our Avatar, but it's good to have someone around to help teach the novices.
[[Army of the Dead]] is, I'll be honest, win-more here. HOWEVER. This can become an infinite combo with [[The Pallid Bust]] and a way to give things Charge. Banish the Army with the bust, get a minion carrying it to take damage (such as by attacking an enemy Avatar), then have the minion drop the bust (if it lived) and the skeleton who just got made from the "Army" taking damage pick it back up, and just keep attacking and picking up the bust. I don't have [[Horn of Caerleon]] in the list proper, but it would do the job.
[[Draconian Bonekite]] is also win-more but I pulled a foil one and I'm going to use it, plus that tap ability can turn a bunch of tapped skeletons into untapped blockers so that's cute.

Magic

[[Raise Militia]] is regularly three mana for four or more bodies but even if it's cast below rate they're all made somewhere useful.
[[Undead Ambush]] is three mana for four bodies unless your target is on an edge or in a corner, in which case probably target something else.

Sites

[[Boulevard of Bones]] makes skeletons whenever an adjacent site is played. It's free skeletons.
[[Open Grave]] or [[Open Mausoleum]] is effectively a second activation of our Avatar in a turn.

Ways To Strengthen Skeletons

Making Them Stronger As Minions

[[Eclipse]] also lets us cast Evil to affected locations which is ok I guess but +1 power is what I like most about it.
[[Death Knight]] is enormously impactful. Nine squares instead of four, and you can move it around? Better than [[Eclipse]].
[[Returned King]] also steals any undead your opponent might incidentally have. Kind of bonkers.
[[Desecrate]] doesn't increase their power on its own but the three [[Desecrated Ground]] in the collection certainly do.
[[Witching Hour]] only makes them stronger for a turn but making skeletons Airborne and increasing their power is potentially game-ending.
[[Sold-out Cemetery]] is free movement at the cost of being a site where you can almost only ever have one minion to defend it. Parking the [[Necromancer]] on top lets you march a conga line forward every turn, though.
[[Wuthering Heights]] is free movement that can reach diagonally. Extremely powerful defensive site, and usable to position our minions offensively to boot.

Exploiting Their Presence For Value

[[Pnakotic Manuscript]] very nearly reads "spend 1 mana a turn to draw a spell" if you put this on your Avatar's site and sacrifice a skeleton to it a turn. If you have a big pile of skeletons on one site, trading each for a spell can be enormous.
[[Zombie Bruiser]] can cast itself from the cemetery by sacrificing a skeleton, so even if 4 power isn't enough to stick around for a while you can just get it back next turn.
[[Bone Spear]] is mostly here as a door finisher but being able to shoot a 3 damage projectile from wherever we can get a minion for 1 mana is pretty significant.
[[Kiss of Death]] is one of the only removal spells we have and any skeleton can cast it!
[[Unlikely Alliance]] is a draw spell that cares about minion rarity. Skeletons are Ordinary, and a little better than two thirds of our minions aren't, so those are pretty good odds for 4 mana to draw 2 or better.
[[Altar of Malachai]] buys a turn at the cost of a token. So affordable!

The Other Cards

Minions That Don't Interact Directly With Skeleton Tokens But Are Still Neat

[[Skeleton Mage]] can recur ordinaries from cemeteries. Still has to meet threshold requirements, but being able to go "surprise! I wasn't out of [[Bone Spears]]!" is fun.
[[Sturmgeist]] isn't Undead but it IS ridiculously powerful. A diagonal step toward any enemy casting Magic AND then if it strikes the caster and the caster dies the spell doesn't resolve. Massively impacts the opponent's game plan if they're heavy on either Magics or Spellcasters.
[[Bane of Aventis]] steals warded minions permanently. On a body that's already 4 mana for 4 power. This is potentially backbreaking against some decks, and my local game stores have plenty of [[Savior]]s running around.
[[Crawling Congregation]] probably isn't very good but it's saved me from dying to [[Firebolts]] on door before so they've got a special place in my heart. Bonus: lets you shoot a [[Bone Spear]] through your own army!
[[Young Master Damion]] is a minion I've had trouble getting real value from but on its face eight power for six mana is good. Every time I've played him the opponent has been able to remove him so the ghouls being unkillable hasn't ever mattered.

The Magic Spell I Didn't Talk About Already

[[Carrionette]] can recur almost any minion in the deck for 3 mana, and there's a good number of spellcasters to be had so "nearby" is probably a lot of the board.

The Atlas

[[Dark Tower]] / [[Gothic Tower]] / [[Lone Tower]] are just really solid and it's pretty easy to find three slots in any Air deck for them.
[[Den of Evil]] is a discount on most of our minions. Sneaking out a [[Death Knight]] for cheap is pretty good.
[[Mirror Realm]] is incredibly powerful. I don't like autoincludes on a conceptual level (which is the primary reason this isn't a [[Toolbox]] deck) and this site is expensive because pretty much no deck doesn't want to run it. It's not as egregious as [[Ring of Morrigan]], but wow. Boy, howdy. What a card.
[[Perilous Bridge]] is a very strong defensive site. This can buy three turns against a faster deck. It can obstruct our army significantly. Deploy with care.
[[The Manor at Daperyll Hill]] is the sort of site that opponents might try to just walk around, but blowing a guy onto it with [[Wuthering Heights]] is funny. Watch out for that four Air threshold, though; this list is primarily Air but four is asking a lot.
[[Windmill]] is the best at what it does. Also the worst at what it does. Nothing else does what it does. And what it does is provide one Earth and one Air affinity.
[[Wormelow Tump]] isn't particularly important here, really, but I like cards that say "can't" on them and this one is pretty innocuous. The thematic resonance of "don't mess with my dead guys, I want to make them alive... ish guys" is pretty pleasant.

The Collection

[[Desecrated Ground]] is a three-of so that every [[Desecrate]] can make one. Banishing a site to transform it into a buff for the minion that just struck it is tasty.
[[Ghoul]] there's four of em in case we [[Carrionette]] out [[Young Master Damion]] a second time. Also in case we swap in the sites that make em again.
[[Those Who Linger]] are just cool. I like having them here. They hint at a [[Silver Bullet]] play we don't run in case someone's resolving a [[Legion of Gall]] and might choose to banish something we intend to use.

Mulligans

Ultimately you want to be casting stuff early and then reliably. Something very strong to build to in an opening hand like if your opponent is on [[Savior]] and you're sitting on [[Bane of Aventis]] don't put that to the bottom and set up sites to cast it if you can. Turn one is always going to be "summon a skeleton," so mostly just make sure your sites and threshold needs line up with stuff to do by turn three. This advice is pretty generic, because the game plan doesn't really revolve around any one kind of card in the deck. Plan to get minions on the board and push them forward to victory, so if all you have is [[Bone Spear]], [[Unlikely Alliance]], and [[Witching Hour]] I'd suggest keeping the [[Unlikely Alliance]] and sending the other two back with whatever site is least useful or most redundant.

Changes

Revision 2026-04-21: updated primer to more usable format.

Updates Under Consideration

[[Forsaken Crypt]] is another way to use the [[Ghoul]]s in the collection, and 3 mana for 3 power without needing to draw a spell to do it is pretty OK. Possible to run out of [[Ghoul]]s in the collection with [[Young Master Damion]] in the deck. Don't love that. That's the same reason [[Those Who Linger]] aren't actually in the maindeck despite how much I like em.
[[Gnome Hollows]] is very good at keeping strong attackers out and our skeleton tokens can walk through unimpeded. There just isn't much room to spare for Earth sites, though, without rebalancing the elements in the spell book substantially.
[[Heirloom Lost]] is really good. It can remove [[Roots of Yggdrasil]] without triggering it. It can replace something like a [[Perilous Bridge]] or [[Great Wall]] to open the way for attacks. Threshold requirements in the deck are pretty greedy, though, so spending a slot in the Atlas on a site we won't even play for mana feels dicey.
[[No Man's Land]] can be enormously impactful at delaying an aggro plan, and it's pretty easy for us to work around it because a lot of our minions aren't made in a forward location anyway. It's also an Earth site and there's not really a slot for the same reason as [[Gnome Hollows]].
[[Rift Valley]] can, by itself, turn a losing position into a winning one. Site movement is tremendously powerful. But it's an Earth site.
[[Sinkhole]] is good in the same way that [[Heirloom Lost]] is but can target sites more generically. Blowing up something next to a [[Boulevard of Bones]] and replaying stuff to the rubble can net extra value from the Boulevard. If problem sites become more prevalent in my local meta this probably crosses the line into the atlas before [[Heirloom Lost]] does but until then I'll stick with affinity-providing sites.
[[Bone Jumble]] / [[Fowl Bones]] / [[Barrow Wight]] aren't very good. [[Bone Jumble]] is probably the best one; in practice it's one mana per skeleton to get an extra attack on a site or a minion that absolutely needs to be removed but at that point you're trading like three, four, or more for one and that kind of tempo loss is game-losing. Ask me and the [[Lugbog Cat]] how I know. However. I really like the sense of leaning all the way into using skeleton tokens, specifically, for value. This deck would be much worse if it cut some of the broadly powerful Undead or other general utility (like, for example, [[Young Master Damion]], [[Crawling Congregation]], [[Bane of Aventis]], [[Carrionette]], [[Sturmgeist]], and [[Unlikely Alliance]]) in favor of these eleven cards. But it would be flavorful. And there's a sense of completeness that comes with including them alongside [[Zombie Bruiser]]s. If this were strictly a casual kitchen table deck in the style of Magic's Commander format I'd do this in a heartbeat, but my local game stores tend to run higher power decks and I'd rather not sit down and expect to trivially lose every time.
[[Occult Ritual]] is mostly here because I have one on hand, no deck to put it in, and this deck runs a bunch of spellcasters. No really solid way to sink that burst of mana, though.
[[Arcade of Bones]] is free lateral movement, protects against [[Murder of Crows]], and is three mana and a card to do very close to nothing. Very flavorful, though, and I'm still not sure I value free movement enough despite thinking it's one of the strongest possible things to print on a card.
[[Horn of Caerleon]] goes ininite with two uniques that the deck already runs: [[The Pallid Bust]] and [[Army of the Dead]]
[[Earthquake]] is very strong removal and we're pretty light on removal.

Skeletons!

@Anathema