Elden Ring Nightreign features multiple playable characters that you can use to hunt Nightlords in Expeditions. There are a total of eight playable classes, with six being available right from the start.
The two classes that you’ll have to unlock are the Duchess and the Revenant. Unlocking them isn’t too difficult, but it takes a bit of work before you can get your hands on them.
How To Unlock Duchess In Elden Ring Nightreign

The key to unlocking the Duchess is going through the first Expedition of the game, where you fight the Nightlord Gladius, Beast of the Night. You don’t have to defeat it, but you’ll receive an item called Old Pocketwatch upon fighting the boss.
This item can be used as a Relic, but you can also give it to the Priestess in front of the Roundtable Hold. Upon giving it to her, she reveals her true self, where she isn’t just a Priestess, but instead the Duchess herself.
You will get a small cutscene, and the Duchess class will be unlocked for you.
The Duchess is a dexterity-based class in the game where you primarily use a dagger to deal damage. She is extremely agile and can easily disengage from bosses and re-engage again to deal massive amounts of damage.
How To Unlock Revenant In Elden Ring Nightreign

Unlocking the Revenant is pretty simple, and you can do it right after getting access to the Duchess. Visit the Small Jar Bazaar and pick up the item called Besmirched Frame for 1500 Runes.
Once you buy the item, you’ll find the ghost of a girl standing in front of Radagon’s portrait in one of the hallways around the Rountable Hold. Interacting with the doll will take you to a boss fight called Night Idol.
The boss isn’t hard, but rather annoying to fight as the Night Idol summons three phantoms that charge at you, while she herself throws spells from a distance. The easiest way around the fight is to pull the phantoms away from the Night Idol.
Take down the phantoms, and then all you’ll have left is the Night Idol. Fortunately, all of them have very little HP, so something like the Raider class can finish them off in a few hits, including the Night Idol.
Once the Night Idol is defeated, the Revenant will be available for playing from the character selection menu.
The Revenant is a Necromancer class in Elden Ring Nightreign who can summon dead enemies as allies while casting spells from a distance. She is quite strong, but needs players in the team who can tank bosses, as her health is extremely low.