[Asriel feels Mettaton's guilt... and in return, Mettaton will feel a heavy anguish. The emptiness of not having a SOUL, the rage and despair from dying and being trapped in an endless, resetting timeline. The sheer amount of guilt when you finally realize how many timelines you've destroyed, the countless number of lives you've toyed with and ruined.

The sheer grief of losing the only person in the world that mattered to you.

Asriel sobs, because that's all he can do. Cry, whimper, and cling to the only monster here with him. The key is removed with a startled noise.]

Į̣᷅̎᷀͢͢t̵̛̤̓᷁̒᷾͢͢'᷊̙᷄̾͆͢͢s̥͇̥᷆̿͢͢ f̸̥̑͗̈́͢͢r̸᷊̗̥ͯ͢͢ő̝͈̬̑͢͢ṁ̘͕͐͢͢ͅ ẏ̮᷊ͨͧ͢͢o̲᷂᷁͘͢͢ͅǔ̮͚̋̆͢͢r̗̼̮͛͊͢͢ s̻̺͓̎͋͢͢o̸̟̎̽͢͢͢ù̹ͦ̓̓͢͢l̖͛̓̃̾͢͢

Ḯ͑᷀.̯͋ͮ.͖̍̐.̧̘̬ w̫̽͜e͗̉͝ p̗̮᷅u̝ͤͫl̦̲᷅lͤ᷇̊ě᷿͝d̐̅̃͌ i̛̺̒t̻̾̈́ o͔̓͠u̇᷁̚ťͮ͆