Gremist is a druid and master alchemist who lives by a pond north of Gedyneith on Ard Skellig, in the Skellige Isles. Unlike most druids, he has no great love for people. By his own account he became a druid precisely so that nobody would bother him with their petty problems, and so that he would not have to pretend to care. He spent a lifetime gathering alchemical knowledge and has no wish to hand it to an apprentice who has not suffered for it. He does have a few friends, though, such as Fritjof, and a drink or two shows a much jollier Gremist.

In The Witcher 3

In Practicum in Advanced Alchemy, Gremist grudgingly lets Geralt help him and sets three tasks before he will teach the witcher anything. The alcohol Geralt brings back ends in a merry, drunken reunion between Gremist and Fritjof, after which the druid keeps his word and shares his knowledge, though not entirely sober. Afterward he sells ingredients, runestones, glyphs and formulae. He also plays gwent in Gwent: Skellige Style.