The chapter opens with a splash. It's not clear who made the splash, but it's clear that the runes were created by a demon master. The runes are so complex that they're hard to interpret, but they've been created by the same demon master who created them in the first place. The only way to figure out what's going on is to look at the sealed runes, which is why the splash is so important. The other three sealed runs need to be looked at too, but that's a whole other story.