When preparing for battle, have a look over the building browser in your settlements to view what units you have unlocked for recruitment. Make sure the Conscription Halls are built in one of your controlled settlements to give you access to some cheap, low-tier infantry units. When you have a level 2 settlement and some money in the treasury, try building the Plateau of Dark Steeds or Den of Outlaws to unlock access to cavalry early on in the game, useful for flanking and giving you an edge in battle.
If you have control of a Black Ark, always attempt to battle within its bombardment range, shown by a dashed circle on the campaign map; this will give you access to the bombardment army ability in battle: a considerable advantage over your foe.
The Druchii are an extremely aggressive race, which comes strongly into play during battle. They have a lot of amrour piecring units: useful for taking down heavily-armoured enemies. At the top of your screen you will see the Murderous Prowess bar which tracks deaths on the battlefield – on either side – with a significant buff that kicks in when the bar is full. You will want to fill this bar as quickly as possible, so kill as much as you can, as fast as you can.
When setting up for battle in the early game, place a line of infantry at the front, such as Bleakswords and Dreadspears as they are the cheaper options open to the Dark Elves at the beginning of the campaign. To the sides, place some cavalry such as Dark Riders to protect from flanking, but also to chase down any routing enemy units to rack up vital kills for triggering Murderous Prowess as soon as possible.
When the battle begins, send your units in as fast as possible to hit that vital kill count as soon as you can, but watch out if the enemy hangs back! If you have any artillery such as Reaper Bolt Throwers, use these to spray ammunition into the enemy to soften their ranks if they are not engaging.
When the Murderous Prowess bar is full, the ability will trigger automatically giving your forces a buff to their leadership, melee attack, charge bonus, armour-piercing missile damage and a big boost to their vigor. They will glow purple for 90 seconds – be sure to engage in as many attacks as you can in this time, as you will be much more powerful than your opponent!