The Binding Blade DLC for Darkest Dungeon 2 has brought two new heroes to the game. While the Duelist is available at the start, you must complete The Lost Crusade quest to get the fan-favorite warrior and pair it with the Abomination. Here's how to unlock Crusader in Darkest Dungeon 2.
The Crusader class has to be unlocked by completing a quest called The Lost Crusade. When you get to the first inn, you will receive an item called Battered Helm, which is a Trophy you need to place on your stagecoach to initiate the quest. This will add some difficulty to your run, so it is not advised to try it if you are still getting familiar with Darkest Dungeon 2.
There are seven stages you need to complete to finish the quest. However, if you lose or abandon the expedition at any point, you don't have to start over. You will start your next run in possession of the last item you found, so you can pick up the quest wherever you left it.
While you have the Battered Helm Trophy on your stagecoach, there is a chance to spawn a barricade encounter. This is a fight against a few soldiers of the Swordsman type, and they spawn with a shield in front. However, sometimes, a Swordsman isn't protected by it.
Focus your attacks on him instead of trying to break the shield, and only once he is downed you deal with the others. Once you win this encounter, you will get the Tattered Banner.
Tip: Bring Bandages because the shield applies Bleeding to anyone who hits it.
The Tattered Banner is a combat item. Equip it on one of your characters and use it on a Bishop (a type of enemy encountered in The Tangle). The banner will give the enemy a buff, but once you defeat them, you will get the Unique Reliquary. This is an item that cannot be opened until you reach another Inn.
Once you arrive at an Inn, you will get a buff for having delivered the item, and upon opening it, you will get the Sanctified Scroll. This is a Stagecoach item and needs to be equipped for the quest to move forward.
If you have the Sanctified Scroll equipped on your Stagecoach, you will get a special dialogue the next time you find an Assistance Encounter. With this interaction, you will get an item called The Rumour of Riches (a roughly drawn map of a treasure that you will need to give to a Hoarder).
With the Rumour of Riches, you can buy the Blessed Blade (top left item on the image). The rusty blade needs care, so you need to take it to an inn.
When you arrive at an inn, the Blessed Blade will be converted into the Helm & Blade item. This is a Trophy, so it needs to go on your Stagecoach for the quest to continue.
This is the final event of the quest. With the Helm & Blade equipped on your stagecoach, the last battle before the next inn will become a special event called The Caged Knight. Here, you will have to defeat the Warlord, and once you do so, you will be able to unlock the Crusader at the Altar of Hope.
For more information on Darkest Dungeon 2, check How to play Darkest Dungeon 2 on Macon Pro Game Guides.