Grief
A hundred foreheads lower themselves to their hearts in winter in grief. There were once many of their kind, the forehead peoples, but now there are only a hundred left after this harsh winter took the rest of them. Their grief is immense.
Imagine if winter was so brutal that there were only one hundred human foreheads left. You lost all of your friends and family. Feel that grief.
ゆう
う, うれ
None
Their grief intensifies because all of the foreheads they lost belonged to youths (ゆう). Dead youths everywhere. Now there's no one left to repopulate the world.
Grief for youths is so painful. No one should have to bury their forehead child.