What lore did I miss?

chaos was told the truth about deltarune by gaster, chaos went insane, chaos got possessed by the dude from inscryption (po3) who used chaos to start the roaring, chaos regains consciousness and gets smacked through my ebbot into the true lab, and that’s about all

Is that the thing that seam was hinting about making with the crystals?

yez

I've only played Chapter 1 so far, btw

W lore