On the way to trick death, wardens had to pay a price and never see the world they reside in, so they might never know if they actually returned to it. Wardens navigate using their newly formed hornes, which help them distinguish the distance and direction.

Warden upgrades were focused on making them better wariors.

You don't have lungs.

Going through the Warden process has liquified your lungs and replaced your breathing system with plants capable of moving the body without any need for air. This change has made you immune to poison but extremely vulnerable to fire.

You know the Druidcraft cantrip. However, you can only use it to grow Skulk Vines. Additionally, when a creature or object interacts with a Skulk Vine, you have 40 ft of walking speed moving towards it independently if they are in open or closed space, and you gain knowledge of the creature type if they are plants, humanoids, or animals. In any other case, you detect the creature but are unable to distinguish its type.

Your ears and horns help you with perception checks that rely on hearing. However, your lack of eyes gives you a disadvantage on perception checks that rely on sight. The DM might also raise your DC compared to other players or simply make you instanly fail (only if sight is the only way of perceiving this, so you wouldn't notice it on the air, with touch vibrations or hearing).

Althought Wardens can't drown, they don't usually go to swim. That is for they can't fisicaly swim, as the are unable to stop sinking to the bottom

Wardens' alignment depends greatly on who they once were. A normal transition makes sure to keep the memories untouched, so their alignment is based on who they were before dying. The process could also be applied to make the person forget, leaving an empty shell or a different person, but those who have tried to play with the Wardens' memories have not ended well.

Wardens speak the languages of the deep underdark.