Inspiring Tune and Battle Ballad are pretty much necessary.

You need Stress reduction to deal with certain Swine enemies.

The Jester has options for both targeted stress relief (Inspiring Tune) and general stress relief (Battle Ballad.) This character will basically act as a sort of stress healer for your run. Stress is a serious problem in the Warrens (mostly due to enemies like the Swine Drummer and Swine Wretch) so you will need to fit a Jester into your party comp.

Come Hither and Mark For Death are good pick-ups.

You should try and pick up the Come Hither and Mark For Death abilities as they deal extra damage to marked enemies, which the Hound Master can do for you. Much like the Hound Master, the Bounty Hunter has a damage boost against beasts.

Cry Havoc reduces stress in the Warrens, which can be run-ending.

Big damage boost against beasts, important in this dungeon.

Lastly, the Hound Master can be used to reduce the stress of your party with the Cry Havoc ability, and stress is a huge factor in the Warrens. He gets a damage boost against beasts, of which there are loads inside the Warrens, and his ability Hound's Harry inflicts bleed damage to the entire enemy party.

The Hound Master is almost a must-pick for the Warrens. Enemies are heavily resistant to Blight, which means you will need to change your party composition and your playstyle.

While Blight might excel in the Ruins, it will be of no use to you inside the Warrens.

Those Stuns, like Blinding Gas, can also provide good crowd control for enemies in the back position. Her skills like Noxious Blast and Plague Grenade can hit each enemy position. The Plague Doctor is a powerful character who deals heavy Blight damage from the backline. RELATED: Best Games To Play If You Like Slay The Spire Plague Doctor

Both AOE and single-target heal abilities.

Plays in the backline and provides support to your party.

The vestal plays in the fourth position, at the back of your party. The vestal can also have the Divine Comfort ability which is an AOE heal for each member of the party. This is a targeted healing ability that can heal between four and nine HP on a hero of your choice. By far the most consistent healing hero is the Vestal, as she will always have the Divine Grace skill when employed by you. You aren't going to get very far without a healer.

Available right from the start of the game.

Good damage boost against the enemies in this dungeon.

Darkest dungeon siren strategy