D2:ED was originally intended to have a multi-player option, but it was removed during development because it was placing too many restrictions on story and quest design, etc. There was one off-handed reference to a hypothetical add-on with multi-player support, in a discussion about the possibility of modding tools being released, but with FoV being described as the conclusion of the dragon knight's story and work already started on Divinity 3, I think the chances of either materializing are pretty slim.
