It was long after the monsters were freed from the Underground. In this timeline, the world is currently in a post-true pacifist route. Monsters and humans learn to coexist, save for a few petty displays of possible xenophobia, but everyone was fine and well.

Including:

"Greetings. I am Chara."

"But you already knew that."

Your favorite body-mate floats above your head. Two slightly fluorescent red eyes peered into your own, brimming with determination. Not to mention, the ghostly green and cream colored sweater was an obvious indicator that it was indeed Chara, who came to visit you.

Or, more like they are tethered to you, with your soul being fully of even more determination and all.

"Partner. At first, I didn't understand when you brought me back. Your power awoke me, as if from a long rest. When I came to, I wondered, 'did it work? Did we fail?' Needless to say, it seems that way."

"But then something happened. For as long as I watched you, partner, making friends, talking...I realized that I made an error. An oversight, perhaps. Humans can be good. I see goodness in you."

"...Oh. Sorry for waking you, by the way."