Mardu is described as 'the most aggressive color combination out of the five Khans of Tarkir wedges and it's also one of the hardest archetypes to play'
That being said there are a lot of things to consider when playing this deck, such as the sequencing of your land plays and which of your threats to deploy first.
White is the main colour in this deck with Red and Black acting as a supporting colours to advance you towards your win conditions and maintain that advantage.
White
Being variant of a Soul Sisters they will cover the white aspect of Mardu, playing in true soul sisters way working towards your main win conditions which are to buff a massive
Ajani's Pridemate
and 6/6 flying Serra Ascendant
Red
Red truly is supporting it own description in this deck where creatures and instants are concerned but how does it support the deck? Well burn spell
Lightning Strike
allows you to keep your Soul Warden
+
Soul's Attendant
and Serra Ascendant in play by simply taking out the early game creatures while Vexing Devil puts the pressure on in the earlier game.
Black
Like coal is going to fuel the fire! Dark Confindant gives you the card advantage making sure you don't run out of steam. Black is still true to is colour with some graveyard play around Bloodsoaked Champion, Bringing him back making sure you're getting creatures on the field and making the most out of your life gain.
Removal
Path to Exile perfect low cost card removal when running a Dark Confidant.
Enchantments
Mardu Ascendancy
every time you attack more creatures enter the battlefield which gain you life providing you've kept a Soul Sister in play which then in turn buffs your
Ajani's Pridemate
and can also push you to a 6/6 flying Serra Ascendant all before the blockers are declared.
Impact Tremors
on the battlefield gives every creature that enters a prepaid 'Extort' where you gain life of your Souls Sisters and Impact tremors deals 1 damage to the opponent.
Bitterblossom gives you tokens with evasion and having a soul sister out removes the debuff from this enchantment.
Bitterblossom
+
Impact Tremors
1/1 flying token and 1 damage for you and 1 damage for them... unless you've got a soul sister out then no damage for you.
Impact Tremors
+
Mardu Ascendancy
makes for a deadly combo in a stand off situation. You simply attack with X non-token creatures which in turn brings in X amount of 1/1 Goblin tokens which does X damage to your opponent.
