That's actually a good question, and I shall answer it. Spirits aren't corporeal beings, and therefore go by different rules. The tapping of energies, especially those regarded as sinister or unwholesome, is actually a good thing. Think of it like trimming a bush or tree to help the whole plant, even though it's nothing at all like that.
And yes, those who can ask not to be eaten should not. But I wasn't about to leave a dangerous spirit, however contained, in the area. I've nothing against spirits, even those harmful to life, but that spirit would have been a problem if I'd let it live.
Arbitrary? Perhaps. I'd grown more wary of spirits since adopting my first. I might still have fed that young shadow spirit, but I don't think I'd have let it in my aura.
Yuck.
I needed to clean my aura.
So first off, no, those guards shouldn't have been asleep, not both of them. I know why, as the author, and it's not just to make things easy on Rhishi.
Honestly? When have I ever made things easy for Rhishi? That's theoretical, not a challenge. I'm sure that at least once, probably more, I've skewed things in his favor.
Instead of against him, which I admit freely that I do.
As always, thank you for your continued readership; may the guards set to catch you always be overworked.