For Kisara, those letters Lee Hi asked Kai to deliver to her one by one until she turned 18 were the only thing stopping Kisara from ending her life immediately.
When the letters stopped, and their conversation ended, after she received the last one, she would let the toxin take her life.
Yes, she knew the letters would stop the moment she became an adult in a few months. She counted the intervals and analyzed the content carefully.
She knew from the format of the writing that it was supposed to end soon. She could somewhat see how long the ink had dried in the paper, to see that it was written around the same time last year. The letter was indeed written in bulk, all to be sent slowly across a year.
Even though it was an airtight plan, she knew. She was prominent with Mana and could see subtle traces using her power, too.
She knew from the start that Lee Hi... would soon die.
