He pops to the fleet, hops them into the next dimension over and drops them deep in intergalactic space, bounces to Nuime and drops a summary on Esarkan, then comes back.

"...you're filth creatures," says the bewildered alien. They genuinely can't conceive of why anyone would ask that question; it makes no sense.

"So...you weren't aware we were people, or you find us an objectionable kind of people - did any filth creatures attack you at some point?"

"No...?"

Filth creatures aren't properly people, but they do think, that's what makes them an abomination. Things that can think but aren't people (meaning: members of this alien's own species) are wrong and need to be destroyed. Surely even a filth creature would know that - don't they see people the same way? How can any thinking creature not react this way to alien beings? This is so confusing.

Bounce - "no, actually, most species get along fine with other species. You guys are probably capable of it too, though I'm curious if the disgust-reaction thing is responsive to magic, that'd definitely make it a lot easier - anyway, you made a mistake. Things that can think but aren't your species are perfectly fine and if you dislike interacting with any of them we could find you an empty dimension."

These filth creatures can read minds, not just control them. This is even worse than the filth contagion of Tseiza-3. It is the end of the world and nothing will ever be okay again.

"Elaneth-imire, can you go get Macalaurë?"

Where's this world's Macalaurë - over there, dead - here's a resurrection path.

"What -"

"Aliens who apparently find the existence of other species deeply inherently objectionable and so kill them every chance they get - do you have anything stronger for it -"

"Sure." He turns off the recording. He sings. They are this alien's best friends, it cares about them deeply -

But these are filth - they're having intense feelings of friendship and caring toward filth - they are obviously irredeemably corrupted, no better than filth themselves - they are overcome by despair and want only to die.

He can fix that too.

Now the alien is happily determined to kill themselves the first chance they get!

"Huh. I'm awfully tempted to say 'kill them all, it'd be a favor, resurrect whoever else they've murdered in the course of this bizarre crusade -'"

"Me too. I suppose we could spare the children."

"This one's a soldier in the army they sent to wreck your planet," Elaneth-imire points out, "it's possible the rest of them won't be quite so zealous. Worth checking, at least."

"Oh, I think we should try a couple hundred variants on getting them into a more pliable state of mind, different songs for it - Cáno can improvise, and can put more into it than he is right now - you should see if you can manifest a power for turning off the disgust thing - I just won't especially mind if the end result is that they all want to die, because what the fuck." 

(Alien can't want to die because alien can't want anything at all, is losing all capacity to have preferences about the world.)

"...I'm all right with trying to manifest a power for turning off the disgust thing but I can't help feeling that mind control songs are a badly targeted solution to this problem," he says. "Like, okay, we mind-control whole planetsful of aliens so they stop wanting to murder us for no reason, then they start wanting to murder us because we mind-controlled them. If I get a power for turning off the disgust thing it'll tend to be nicer and have fewer side effects."

The alien's urge to die does not appear to be located wholly in its preferences - it should die because it has been corrupted by filth, regardless of what it wants.

"I don't think this scales as a fix but I'm trying to get a useful feel for what it is."

"Well, fair enough. But I think you might've broken this one already."

"All the more reason not to run through a dozen of them trying to get information. Subtle artists might be able to do something, come to think of it."

(He lets the songs wear off.)

The alien goes back to being despairing and suicidal.