DP is calculated by adding up the raw DP and then applying DP modifiers (mods).
Raw DP is made up of your specialist DP units and your elite DP units. Goblin notably does not have an elite DP unit and instead relies on Shaman as its sole dedicated defensive units. Troll uses the same unit (Smasher) as both elite OP and elite DP unit.
Most races have a small amount of DP on their elite offensive units. For example, Human Cavalry have 6 OP and 3 DP. The 3 DP is referred to as turtle DP.
To turtle means to either invade but leave a significant amount of turtle DP at home, or to not attack and keep your offensive units at home.
Units without turtle, such as specialist offensive units and Dark Elf Spirit Warrior pose a risk to attackers, who might gain land and not be able to defend it after entering the range of a new, stronger attacker.
- Magic: everyone can cast Ares' Call for +10% DP, but some races have even more powerful defensive spells; Halfling and Icekin.
- Guard Towers: a modifier building often used later in the round, or early in the round to gain speed, especially by races with expensive or inefficient DP units.
- Walls: a slower and efficient way to grow your DP with castle improvements.
- Morale: a multiplicative bonus which can lower DP bonuses.
All DP mods, except for morale, are additive (summed up together):
[Spell] + [Guard Towers Bonus] + [Walls] = DP bonus
If morale is less than 100%:
( [Spell] + [Guard Towers Bonus] + [Walls] ) * [Morale Penalty] = DP bonus
If you are calculating a potential target's DP mods, make sure to deduct your Temples bonus from the target's DP bonus (down to a minimum of +0% DP mods).