I think principal might work for you. It's used fairly frequently to describe the primary people involved in things and the following is listed as one of the (chiefly legal) definitions:
a person who authorizes another, as an agent, to represent him or her.
FTDinclined to judge too severely; "hypercritical of colloquial speech"; "the overcritical teacher can discourage originality" also Excessively and unreasonably critical, esp. of small faults.
M.W says: criticizing other people or things too strongly or too often
A person who is hypercritical of everything one does, says, or writes can be extremely disheartening and demotivating. Think of a hypercritical parent, partner, teacher or manager whose exacting and severe behaviour can actively discourage initiative and creativity in their listeners.
Best Answer
The antonym of nomad is nonnomad. It is mentioned in dictionary.reference.com also.
Examples from Google Books:
Note: The hyphenated form non-nomad looks like more common based on Google Books result.