Flowey

Lonely prince waits,
Hoping secretly to end
The madness started.
'The world will reset again,'
he thinks as he falls, once more.

Undyne

Even with her strength,
She begins to melt away.
Trying to hold on,
She screams, an eagle's proud scream,
Even at the brisk of death.

Napstablook (and Mettaton)

Lonesome, forgotten,
Tuning in to the echoes.
Echoes of the past.
The star grins, falling apart.
Now both of them are broken.

Asgore

As he falls apart,
Secret prayers are fulfilled.
With a smile he
Gives up and lets go of life.
Hoping to join his children.