Swallowed Whole and Supernatural Area Affects?

[RexDart]

So today our party was fighting this giant Darkmantle-ish monster (turned out to be a half-Darkmantle/half-Dragon aberration.)

We had extreme difficulty with the monster's Darkness(Su) effect, which essentially cannot be dispelled or overcome by magical light spells. (Nobody had any real ability to fight in magical darkness, and the guy who had the Staff of Eyes was absent today.)

To make a long story short, the cleric polymorphed into a Tendriculos and swallowed the thing (annoyingly, the Tendriculos' paralysis effect was negated by the Darkmantle's inherited draconic immunity to paralysis, but that's a whole 'nother thing.) So there was this great D&D kaiju battle that essentially nobody could see.

Anyway, the question arose: When the Tendriculos swallows the Darkmantle, does the Darkness effect get blocked, or does it extend beyond the Tendriculos' stomach? The DM didn't know of any RAW that would give an answer, but ruled that the Darkness effect was indeed blocked.

[Tzardok]

The darkness ability of the darkcloak functions like the spell darkness. The area of the spell is an emanation. Emanations don't affect anything behind total cover, i.e. they can't permeate solid barriers.

In short, your DM's answer is the RAW answer.

[MaxiDuRaritry]

Note that the darkness produced by the darkness spell is less like a total blackout and more like everyone inside it's got astigmatism, with the lights turning down a bit. Of course, if it is totally black already, the darkness spell actually brightens everything up a bit, so go figure.