Caelus

Credits to the Honkai Star Rail Fandom Wiki

Caelus' Backstory
A boy who boarded the Astral Express. They chose to travel with the Astral Express to eliminate the dangers posed by the Stellaron.

Caelus' Personality
Caelus consistently upholds a composed and impartial demeanour, yet occasionally interjects with serious, unrelated, or humorous remarks, even in serious situations.

Furthermore, Calus demonstrates a keen inclination for exploration, actively seeking interaction with a diverse range of objects, often resulting in perplexed glances from his teammates. Such idiosyncratic behaviours include aimless wandering and an inclination to inspect trash cans.

When embroiled in combat, however, Caelus' personality undergoes a notable transformation, revealing an intense and destructive disposition, driven by passion and ferocity. It has been noted through his ultimate animations that Caelus seems to have a more aggressive outward demeanour in battle.

Story 1
You don't remember much.
You're not from around here, nor did you come from elsewhere. You're not going anywhere—
Just then, that indistinct voice whispers into your ear. That sorrowful and tender persuasion, that deceptive goading...
The seeds take root. You open your eyes, and the speaker is no longer there.

But there are more and more voices, and they are getting clearer and clearer.
Some give easygoing care, some calmly provide advice, some speak firm support, and some gift gentle direction...
You see the silken thread being woven to form tomorrow.

A huge beast descends from infinity,
golden pupils stare down from the darkness,
and you are no longer abandoned by the past.
You will also set upon a long journey,
and the thorns you have stepped on have become your path.

The train whistles, wishing you a successful journey to the coming future
...by your own will.

Story 2
You have arrived at the "City of Preservation."
Behind the snow curtain, the wind lashes like steel blades, but the kindling burns on.
Distant lands won't hear them, and the earth trembles in kind, with only the wailing crowds braving the wind.

After facing foreign enemies, the Eternal Freeze, and reality's fissures, rot begins to fester within the fort.
You try lending a helping hand but are forsaken.
Some once looked down on you and misunderstood you, but still, you stood by their side and helped them find their way.
More care about you and worry about you. They face their suffering and find the cure for the distressed.
Eventually, they come to your side.

In the ice and snow, you are like a fire, protecting the soul of this world
...Even though you must scorch yourself day and night.