Magi

[Kraco]

I believe magi are able to control both types if they want. Though it's hard to see Aladdin, for example, wanting to control the dark rukh, at least for now. It might affect the magi's personality. If ordinary magicians can control both with some tools, like those at Magnostadt to a degree and definitely the Al Thamen villains, then it would be strange if magi couldn't.

[Buffalobiian]

I believe magi are able to control both types if they want. Though it's hard to see Aladdin, for example, wanting to control the dark rukh, at least for now. It might affect the magi's personality. If ordinary magicians can control both with some tools, like those at Magnostadt to a degree and definitely the Al Thamen villains, then it would be strange if magi couldn't.

Ordinary mages can only control Dark Ruhk. That's why it's so enticing, because up till now Ruhk was an energy source that only Magi could manipulate.

That's the only advantage I see from using Dark Ruhk, since White is in such abundance in the natural world. Dark Ruhk seems to stem from a source of hatred or evil as opposed to nature. I expect it to possess a will or attribute which, as you say, may have side effects on the user - if not make it outright incompatible with good-natured magi. If you're channeling it with tools, then it might not have such a significant effect.

I think it's way to early to just assume Scheherazade is a non-villain. I mean, she's probably not, but there's no reason she couldn't be.

Her country uses slaves, and she seems to consider Titus to be less than human (whether he really is human or not is yet to be revealed), so she could well be someone to fight against.

[Kraco]

Ordinary mages can only control Dark Ruhk. That's why it's so enticing, because up till now Ruhk was an energy source that only Magi could manipulate.

I suppose that would depend on the definition of control. Magnostadt is collecting a huge amount of rukh from the 200k goi, and I believe most of it is used to power the city itself plus any magical tool manufacture (although these would overlap), including those that require converting it to dark rukh. We haven't actually seen even a glimpse of the tool manufacturing process, so it's hard to say if they all require converting to dark rukh, but I'd find that unexpected, until proven otherwise. Especially since the teacher said they knew little about the dark rukh until 12 years ago. Surely manufacturing tools is an older art than that.