Defenders focus on protecting themselves and attack when surrounded. They can sacrifice their HP to deal damage, but their Aura ability can make them a permanent field unit. They have excellent HP and Defense making them difficult to injure, let alone knock out, but as a bangaa class they lack Resistance.
Their abilities are suitable for the Templar if building a support unit. Defenders are often overlooked compared to the Paladin as they lack Cover to protect other units, but they can deal massive damage to opposing units if surrounded.