A lubberkin (Polish: kłobuk) is a friendly household guardian spirit created from a botchling through Aymm Rhoin, an elven naming ritual, during which it is given a proper name and a burial under the threshold of the family estate. A lubberkin looks very similar to a botchling, though the main difference being its ghost-like, glowing, white aura and relatively passive behavior.
Depending on one's actions in Family Matters, one can turn the botchling into a lubberkin that Phillip will name Dea.
The game is relatively faithful in portraying this old belief, as in Polish folklore the poroniec also turned into the friendly kłobuk (read: "kwo'book") spirit when a stillborn is buried properly under the threshold of the house.
See the GWENT standalone game version card:Lubberkin