sooooo can someone explain to me what a leyline is?
from what i understood it's the roots of the irminsul that store memories, but the story seems to treat them like they can do other stuff.

are the brains of teyvat's people empty? if you hit your head really hard and lose your memory how does that tie into the leylines?
why couldn't the people of natlan leave despite the lord of the night rebuilding their ley lines during the cataclysm