After William left, Seren fell into a depression from which she took a long time to recover. She didn't leave her room for a month and lost more than ten kilos. She looked emaciated, and when she first came out, the people who saw her mocked her, shouting that she was a walking skeleton. Seren didn't care.
After a month, she regained consciousness and remembered that she had promised to become even stronger. She couldn't catch William being depressed and not leaving her room. That's why she had to get stronger. She started training again, but her body had become weak.