Durthu is an Elder of Athel Loren, a Treeman so ancient that even Ariel's millennia-long existence pales in comparison. It was he who first forged a union between Elves and forest, and who argued with his fellow Elders that the binding be made permanent. In those days, he was ever a friend to the Children of Isha, always willing to help them broaden their understanding of forest and Weave. Alas, those days are long gone. Centuries of destruction and carnage have taken their toll on Durthu's valiant spirit. He bore witness to the rapacity of blooded life, and of the wanton destruction it has heaped upon his homeland. He has seen untold acres of trees felled for kindling or from simple spite. He has watched, time and again, as the Elves have invited calamity on the forest through an inability to sever their connection to the outside world. Worst of all, he has seen his fellow Elders fall, one by one; some slain by their own foes but most destroyed by the enemies of the Elves.
↑Armour-Piercing: The damage of armour-piercing weapons mostly ignores the armour of the target, making them the ideal choice against heavily-armoured enemies. They are often heavier and attack at a slower rate though, making them less efficient against poorly-armoured targets.
↑Armoured: Armoured units can block damage from any source apart from Armour-Piercing damage.
↑Forest Spirit: The spirits of Athel Loren are able to shrug off most mundane attacks, causing magical damage in turn before melting into the forest from whence they came.
Durthu is not a regular lord, but a huge monstrous unit which dominates in melee, similar to Kholek Suneater. Keep him away from powerful units with anti-large bonuses and fire, but make sure to take full advantage of his titanic presence on the battlefield. He is a powerful melee fighter and a solid caster which makes him a strong anchor on the battlefield.
Durthu's immunity to attrition for his army allows his to sink into bankruptcy without penalty. The usual penalty is that your units take attrition as they desert, but his army is immune to that, potentially as an oversight from CA. Because factions under bankruptcy won't replenish, if you primarily use Treemen and heal them before the end of every battle., one can maintain Durthu's army regardless of how bankrupt they are.