Nokris was Weak in strength unlike his brother Crota, yet Strong in mind. So he used Magic, Necromancy, Alchemy like the Wizards do. Nokris though was Male, so he looked different he chose to be male as he had a choice on what and who he wanted to be and do. It's set up as follows by Present day Hive: Worm gods Oryx Savaithun/Xivu Arath Crota/Nokris/Daughters Of Oryx/Dull incaru. Children of the Children (Hash) Brood Queen's/Ascendant Champions Knights (Male) Wizards (Female) Acolytes Thrall/Oger Larva The Thralls and Acolytes have no Sex(Biologically) Knights and Wizards both Control a Set amount of lesser Hive, Acoylets Control a Set amount of Thralls. If a Knight dies, an Acolyte Takes the Knights place. Same for the wizard, same for Thralls. Once they become a Knight there then a Male, and wizard, Female. It continues up until Ascendant Champion and Brood Queen. As to be a child or and a Ascendant Hive you have to be chosen by either the Children of the Children or by Savaithun/Xivu Arath themselves. Crota chose Hash as she was as big as an oger and stronger, as a Thrall, yet she liked magic and alchemy more than brute strength like her father. Edit: on the "Witch", I believe Savaithun is the only one with that title as she was the First.

Hive can change their sex, depending on the need. Usually if the mother dies, the father will alter his sex, similar to clownfish. I believe Oryx was a wizard. Bonus trivia, Ogres are just giant Thralls!

Hive don't have hair or horns, they are all bald and wear hats. lol

Yes, Nokris is the only male Wizard. Both Knights and Wizards can be male or female, but evidently due to the emphasis on carrying out the Sword Logic, it’s fairly taboo for a male Hive to not become a Knight and generate tribute as their life’s ambition. The naming of Wizards came from early Guardian encounters. They labelled them not knowing they were female, but I believe some do call them Witches (especially the Witch Queen). Yes, Wizards have legs...somewhere in there.

A lot to unpack here. So lets start off with the first question of Nokris being the only male wizard. Yes I believe he is. Second question being of why there arent any males in the wizard population is because all of the wizards are meant for breeding and making more hive. Third question I have no idea. Final question im gonna say yes.

Yea why is that?

Yes, yes, kind of, and yes