Seeker is one of the three new Survivors added to Risk of Rain 2's Seekers of the Storm DLC alongside Chef and a more hidden third unlockable Survivor. However, Seeker is available by default while the other two need to be unlocked. This makes it a lot easier for people to hop right onto Risk of Rain 2 and try out Seeker in a multiplayer run. And, when it comes to multiplayer, Seeker is incredibly powerful, they're the game's biggest example of 'support-type' Survivor, and their Tranquility mechanics add a lot to the game overall.