Given that this is many, many resets later, Eira and Stella have become one.
Well, mostly. Sometimes one personality shines out, but normally, they are one and are referred to as Snow.
Snow is normal, and the main speaker.
Stella is in italics, although she doesn't speak often.
Eira, when she speaks- which is very rare- is in bold italics.

•••

Eyelights locked onto two people- a human and monster- in a pool of stars, Snow growled lightly. Her left eye glowed yellow for an instant before shorting out, as she didn't want to waste energy to maintain it.

"That... that is the kid who's killed me in the Last Corridor so many freaking times. And I'm supposed to rescue them from the Voidpool? Fresh, I'm doubtful of your sanity right now," grumbled Snow.

"Brah, I'm pretty sure that everyone in this radical Multiverse doubts my sanity. Just... please. For once, just trust me. This kiddo isn't the one whose killed you so many times. They have a good SOUL. Plus, the kid with them is a young boss monster. He'd probably be sad if you didn't save his sister."

"Fine. We'll listen to you. But if they hurt anyone, they'll be on thin ice."

"Nice one, brah."

"Thanks. Now, for the last time, are you absolutely sure about this, Fresh?"

Fresh nodded, wading into the shallowest part of the Voidpool to grab the paw of the young boss monster, who floated aimlessly near the edge of the star-filled water.

Snow's form flickered, and the short skeleton was replaced with a petite black dragon, just over five feet long including the tail.

Spreading her wings, she took flight, swooping above the pool to grab the human by the hood of their jacket and pull them to the side, where she could safely get them out.

Reverting to her normal form the instant she touched the black sand surrounding the Voidpool, Snow waded in after Fresh, grabbing onto the human's green jacket. She grumbled, but despite her distrust of humans, she knew that Fresh had spoken the truth. Besides, anyone who ended up in the Voidpool had nowhere else to go and was a part of something important, some greater plan.