Long ago, when Alste still lived in the cult of Kiaransalee - before the first manifestation of the Urge - she mostly spent her time running small errands for the adults, like the other children of the community.
Watching, listening, retrieving or delivering goods, cleaning ritual halls, things like that.
One of these tasks was delivering food to a group of necromancers who had set out toward the “Buried Realms” in yet another attempt to find something useful there (the clan’s leader was obsessed with Netherese artifacts).
Long story short - Alste didn’t find any of the necromancers (even though she followed the map precisely) and ended up getting lost herself, stubbornly circling back to the same place over and over again.
And when she finally collapsed from exhaustion after wandering in loops, something suddenly dug into her thigh.
A small bat - one of those swarming the caves of the Underdark - had been caught in a magical trap and pinned to the ground.
And although the bat was already severely weakened, having someone try to sit on it, to put it mildly, did not improve its mood.
Alste’s first instinct was to put the little creature out of its misery. Perhaps not in the most merciful way.
But at that moment, she felt the full spectrum of the bat’s emotions. It was probably her first manifestation of blood magic - her first true connection to another living being.
So she carefully freed the bat and examined it.
The bat looked back just as carefully.
And Alste realized she could understand it. The bat could help her find a way out - bats are excellent at navigating space - but it was far too weak.
Alste couldn’t find her way out on her own, but she could offer the bat her blood.
Later, when Alste was being trained by her mentor (an experienced blood sorcerer), he repeatedly told her that this was one of the greatest foolishnesses a blood mage could commit - to use their blood not as a weapon, but as a gift.
If such an act is accompanied by mutual benefit and - gods forbid -sympathy toward the “recipient,” it leads to what is known as a “blood contract.”
Between mage and "victim", a bond is formed - not just a connection, but mutual dependence.
Nine-year-old Alste knew none of this, nor did she even realize she possessed any magic at all.
The bat was fed, recovered surprisingly quickly, and indeed led Alste out of the labyrinth of ruins filled with traps.
And stayed with her - surviving the death of the necromantic community, Alste’s escape to the surface, her rise as the head of a cult of Bhaal, and all the other "cheerful events" that followed.
(honestly, it helped her more than once during her frequent episodes of rather catastrophic sense of direction.)
The contract with Bat gave Alste a noticeable boost in agility and significantly enhanced her hearing.
Bat - which from that point on was indeed called Bat - gained increased resistance to wounds, diseases, poisons… and simply kept living, very much alive and well.
Despite the fact that, by bat standards, it really should not have been.
Alste cannot harm Bat, and Bat cannot harm her either - since harming one’s bonded counterpart would mean harming oneself.
And in a way, it is probably the closest bond she truly has with any living being.
