"...perhaps it is the will of Mara."

"And regardless of whether it's the will of Mara it's most certainly the will of Ruby.

"...so, why don't we just ask them if that's what they're doing? And then if it turns out they are doing soul-affecting necromancy we ask them nicely to stop or else, and then they'll pick the else, and then we make them stop."

"You're going to do this regardless of whether we help, aren't you?"

"'Course. You've met me."

"Yes, and I'd rather you not die, so fine, I'll help."

"And I as well."

So that determined they take down their privacy spells and walk over to the mages. "So, out of curiosity, why did you leave the College?"

"Guess."

"Is it perchance soul-affecting necromancy."

"Oh good you're more than a pretty face."

"I see. Okay. So, I want you to stop. I am not, once again, here on behalf of the College. I am here on behalf of me. And I find the practice extremely offensive."

...she blinks at him slowly. "No? No. We will not—do you even hear yourself."

(Ice mage is getting battle-ready, though.)

"Mmhm. Let me rephrase: stop or else."

"...you're a funny guy. Taking you apart is going to be fun."

It proceeds predictably from there.

    "Weaklings," says the Dremora Ruby summoned, spitting on the corpse of one of the mages.

"They have probably warned the mages inside of our presence. We should be ready for a more thorough defence."

"I'm really starting to feel the whole 'most mages who leave the College were Apprentices' thing, though. Not that I think that the fact that we were promoted immediately makes us invincible, but..."

"I know what you mean. That fight was sort of anticlimactic."

"Apprentices or no, they will have numbers on their side. We will need to be careful."

"Not just careful; strategic. And if this keep is similar in architecture to the other one I've been to, our greatest asset given the disparity of numbers will be hallways. We should avoid being in large rooms or places where they can surround us. If we can force them to walk single file through hallways they will be much easier to pick off."

"We have to assume they'll be aware of this weakness. But also, we should go now because nowhere is as open as outside."

The main door into the tower is barred from the inside, but after looking around some they find a pair of doors partially covered in rubble that they can clear enough to go through which leads to the dungeons.

Thankfully this time Sanguine doesn't strip them all naked. It'd just get in the way.

The Dremora scouts ahead, as excited for battle as it always is, which works great coupled with its lack of concern for its own physical safety. It can be their canary: since Ruby can tell when it's destroyed and it will keep attacking whomever it finds until it either kills them or dies, there's no way the mages can hide from them. Which is, you know, still true of regular Atronachs, but the Dremora is more powerful than anything Ruby and Onmund could otherwise summon so it has that going for it. And ever since acquiring this staff Ruby has made a habit of carrying lots of soul gems* with him and filling them up with the souls of animals they kill for food (or just because they were attacked first), so the staff isn't likely to run out of charge here.

(* Soul gems can be used both for enchanting new items and for recharging enchanted items.)

But if they play it too defensively they'll at best get stalemated—even if the three of them are more powerful than the local mages they're still outnumbered and their respective magicka regeneration rates will let them just tire each other out indefinitely—and at worst boxed in and killed. So they do need to advance and up the pressure.

The worst that can happen to them is the mages all holing up inside a large room with a single hallway entrance so they can focus fire on Ruby, Onmund, and Erandur as they step out one by one. They don't have much of a plan for if that happens except "raise their dead as zombies*"—to deny the necromancers corpses and to create some inside pressure, though none of them are particularly good at necromancy—and "hope in a direct battle of endurance they can last longer".

(* "Zombie" is the name given to a dead creature that has been animated with magic into a mindless automaton. It does not trap or restore the soul of the target—and in fact it is a good counter to the target being reensouled because zombies are short-lived and turn to dust once the magic animating them runs out.)

But for the moment they have to contend with badly-maintained dank and dark hallways and partially-flooded rooms leading into the keep dungeons, abandoned long ago given all the work necessary to dig it out. "State of disrepair" does not do this mess justice; it's properly crumbling.

They don't encounter anyone for the first while, which the Dremora finds terribly disappointing, and which the mortals find worrying. It might indicate that the necromancers are grouping up and fortifying.

It's also nerve-wracking. Walking along dark places, keeping his guard up all the time while nothing at all happens but not being allowed to relax because something could happen, the complete silence only broken by their footsteps and breathing, it's just intensely anxiety-inducing.