Here's what I thought. From the previous chapter (chp.282), Mappy said that there was a cave where you age faster than normal. Meaning that cave or "space" has a kind of property which speeds up the flow of time, which is the opposite of the back channel. And from the previous chapter, komatsu...
It's not that the seven beasts are strong enough to oppose Moon, but they're the creatures that Moon cannot swallow because they have the ultimate safe zone (with ANOTHER passing on through the back channel makes the area a safe zone). Moon would probably defeat them easily in some other way...
