[Hello Eggsy. While Loki's busy with something else, Hiro's going to take it upon himself to address the question here. Beyond bad doesn't even begin to cover stuff here. For the most part though Hiro appears to be kinda patient with the questions, only a tad annoyed by the fact that they're being questioned about facts.]

We really know because we actually saw the things first-hand. Kinda funny how that works. [Hiro, no.] ...the vision came to a couple of people months ago back in the winter and it recently came back last month. This isn't the first time people have had visions of things in this world and have seen them come true months later. If we hadn't seen the hundreds or thousands of shard monsters hanging out in the rings inside Troichean Beinn I'd be a little more skeptical, too.

Fact is they're coming. We just don't know when and instead of waiting, we wanna start preparing for stuff now. Be a little ahead of the game.