Myxir is a Water Mage living inside the New Camp alongside Saturas. Alkimia Interactive has publicly listed him among the named characters being recreated for Gothic 1 Remake, and has confirmed an expanded quest line built around him.
Expanded Quest Line
Alkimia has confirmed a new Myxir-centred quest in the remake. The Nameless Hero helps Myxir acquire a new spell on the coast near the Colony, which gives the player a reason to explore parts of Khorinis that the original 2001 game did not focus on. This is one of the remake-specific additions Alkimia has cited as part of the roughly thirty hours of new camp-specific quest content layered on top of the original campaign.
Water Circle Role
In the remake's fiction Myxir is part of the Water Circle proper, which means his work feeds the New Camp's central project: researching ways to break the Barrier. His expanded coastal questline ties his personal magic research into that broader political and magical agenda.
Relationship to the Hero
For a Hero pursuing the New Camp path, Myxir is one of the senior Water Mages the campaign brings into focus. The expanded quest gives non-mage Heroes a tangible reason to engage with him as well, since the spell-acquisition errand on the coast is structured around exploration rather than purely Water Circle initiation.
Comparison to the 2001 Original
Alkimia has been explicit that the Myxir content in the remake did not exist in the original 2001 Gothic. The character returns from the source material, but the coastal questline is new for the remake.