Remnant 2 is filled with traits that give special bonuses and buffs to your character. The Forgotten Kingdom DLC introduces four new traits, and the Leech trait is one of them.
How to get new DLC traits! Leech, Chakra, Resolute, Gifted/Remnant 2
If you’re looking for a versatile trait that will fit well into any build in the game, Leech is the trait to go for. Here’s how to get the Leech trait in Remnant 2: The Forgotten Kingdom.
To obtain the Leech ability in Remnant 2, you must visit the dormant N'Erudian facility in N'Erud with a friend in co-op mode and ask them to kill you by locking you out of the main control room and releasing the poisonous gas.
To reach the control room, head towards the main bridge of the Dormant N'Erduain facility and turn right towards the ledge. Below you is a platform that you can jump onto. The platform goes through a narrow passage under the bridge and leads to an elevator up to the control room.