What this deck is trying to do

This deck is all about maximising the value obtained from Ward. It has a lot of aggro cards, but should be played in a much more controlling style.

Charge turns the 1 Mana from Ward into direct damage (if you have the mana you can ward twice).
Lethal turns the 1 Mana from Ward into clean minion removal.

Your opponent will not want to trade their 4 power minion into your Pit Vipers with Ward, so you end up getting board control with weaker minions. For this reason you sometimes need to watch out for your opponent trying to race you.

You almost always want to play your minions with Ward. Play your Vipers on turn 2, Scorpions on turn 3 and Powries on turn 4. It's very rarely worth playing these minions strictly on curve without Ward.

There are 4 Forges in the Atlas, using a Lance on your warded minion with Lethal means you get to kill 3 minions with the one card: One from the first strike given by Lance, one from the Ward and one from the minion itself. This is extreme value.

Because you are getting so much value from each card and the cards are relatively cheap to cast, the key to winning is often securing your sources of draw. There are many sources of draw in this deck:

Draw cards

Char Omphalos (left unchecked this will win you the game, mild anti-synergy with other artifacts such as whip and wiccan tools, but totally worth it given the benefit of drawing two cards per turn)
Pact with the Devil (combo with Wiccan Tools for a draw 4)
Grandmaster Wizard (high cost, but very often worth it, play on a turn where you remove opponent's board)
Morgana le Fay (protect her with ward to get maximum value)
Searing Truth (use this mainly for draw, but also late game kill spell)
Sir Pellinore (can kill a 6 power minion immediately and draw a card, ward is a bonus)
Archangel Gabriel (give the spell to a well protected minion if you can't cast it the turn its played)
Blink
Wiccan Tools

The Value Play

The highest value play is putting a Whip on one of your many Lethal minions and then warding it to make it hard to kill. This combo often completely controls the board, and your opponent will be reluctant to want to spend cards getting rid of it. If your Lethal minion happens to be your Grim Reaper, your opponent will have to kill it, or else they will just start having every minion in their deck banished.

Kill combos

Bull Whip + Grim Reaper / Pit Viper / Scorpions = Kill any adjacent minion (before or after movement)
Blaze of Glory + Grim Reaper / Pit Viper / Scorpions = Kill all enemy minions in 9 nearby squares (this is disgusting)
Avenging Angel + Ward (on turn after your minion died) = Kill any minion nearby your site and leave 3 power airborne minion behind (Avenging Angel can often be a lowkey MVP)

Site Play

The most consequential site is probably Wuthering Heights. If you can play this on any of the central 6 squares, the amount of movement options it gives you is ridiculous, especially with all of the charge minions in this deck.

Ersatz Platz is sometimes regarded as too slow, but this deck is much slower and more controlly than you think. It can fetch:

Haystack (if your opponent is playing a combo deck that relies on digging)
River of Blood (if your opponent is relying on healing)
Mudflow (if you're struggling to deal with burrowed / submerged minions)
Iceberg to tech against mono water

(note I am still testing this Ersatz Platz inclusion, if in doubt, just replace it with two copies of river of blood)

Prioritise Forge / Lance on your warded Lethal minions.

If you are struggling to deal with Defensive sites, you can swap in Fields of Phyxis for the Treetop Hideouts

Dealing with the Defence

Sinterfee is there to stop many of the defensive sites (Troll Bridge in particular). If you can manage to play Sinterfee with ward and stealth (from Treetop Hideout) your opponent will find it very difficult to remove.

You must prioritise killing:

Bane of Aventis
Winter Nymph
Order of the Pale Worm

Win conditions

Value and patience - Your cards will be getting so much value from Ward and Lethal that you can just grind out your opponent on card advantage. This works particularly well if you have secured some early sources of draw.
Boudicca - You will often have at least one or two minions on board, Boudicca can just come down and get you so far ahead you end up winning the game.
Infiltrate / Betrayal - such a high value play that your opponents often will not recover. Be patient with both of these cards.

Ward, Whip, Sythe

@Smucas