You're zipping along on a scene where a major character's new powers are revealed.
As a sideline, the scene is also going to characterize a minor character, establish the rules of magic, and foreshadow what's going to happen to the minor character. (Poor fellow. Tempting nemesis is unwise.
Read a witty little bit recently where someone talked about the changes for the worse with wizards, since the happy days of Gandalf who kept a magical sword to do his fighting.
Wizards have a bad habit of creating monsters. This on top of their being prone to making knights who serve them and not the king -- or even sanity. But monsters are something else again.
Hmm -- perhaps this other set of necromancers does not live in another land of shadow.
Perhaps they live in a wide-open sunny land. Hmmm -- farther north, I think, so it's colder, and sometimes it's dark enough for anyone in winter, when it's truly cold.
But that's the advantage of not requiring night for the necromancy: great peril for the heroes. Especially since the land can not support so many, so they have to cover more land with few people
A necromancer wants to show off to a boy. Not just to knock his socks off -- which would be hard to do after the necromancy he's seen in the last months -- but to impress him with their magic.
I was just thinking that I shouldn't repeat too many, so as to not understate their number, and so another bit necromancer was needed, and then no, there can't be too many, or they would have killed each other in bad temper and lack of resources. . . .
On reflection, there are certainly dozens, because many escaped in the final battle. But probably less than thirty.
I should list them. I probably have a dozen already. And then I work out how they repeat in scenes.
Knights are more powerful but much more focused in the magic they can perform than wizards are, and also it's a one and done enchantment, but it has to suit them.
Thing is, she's a magical knight. She has unusually many magical abilities, and she has many magical objects to help her. Her lair has walls of rocks, not dressed stone. Also deep moats, and walls of fire. (The last, for reasons, is the least problem.)
Fortunately, fights in a novel don't go like fights in a RPG. Or even a comic. The technical details of a fight don't get the weight as the impact on the characters. (There's only so much you can do to draw out even the longest fight on the page.) And the evil knight can be quite melodramatic.
So if you're strong-willed, and a wizard tries to turn you into a magical knight with a powerset that doesn't really match your character, you end up with magical powers that don't exactly match
A wizard can learn to do a lot of things, even ones that do not seem natural to their character. A knight can do a set of things, determined by the intent of the wizard casting it and their natural character, though much more powerfully. (Unless they are wild, in which it's determined by their character, solely.)