Location from Undertale / Deltarune by Toby Fox
The magical wall sealing monsters underground — breakable only with seven human SOULs, standing between an entire civilization and the sky they've never seen.
The Barrier was created by seven human mages after the Human-Monster War, sealing all monsters underground. It requires the power of seven human SOULs to break — Asgore has collected six, and the protagonist would be the seventh. This is the game's central tension: Asgore needs your SOUL to free his people, and you need to survive. In the True Pacifist route, Asriel breaks the Barrier using the combined power of every SOUL — human and monster — in the Underground. The ending shows monsters seeing real sunlight for the first time.
A shimmering, translucent wall of light at the end of New Home — beautiful and impassable. It doesn't look threatening. It just... doesn't let you through. The light it produces is the closest thing to sunlight the Underground has.