A man who is remaking New York and believes he is saving it, and who is the largest and most easily wounded person in every room he enters.
Fisk is the best villain in this material and the reason is structural: the show introduces him a full quarter of the way in, and by then it has spent hours on his money, his associates and his taste, so that the man himself arrives as the last piece rather than the first.
He is also written as somebody who cannot hold a feeling without it becoming violence, and the series is very careful about when it lets that show. The scariest thing he does in his first season is have dinner.