Who did this?

Alison has been supporting Draven from the beginning and is well-versed in everything about him. She had some magic knowledge, though, and she used it to poison Richard's mother. Since no one could determine the true cause of her passing, it was only a supposition. When Alison learned Alfred was Richard's trainer, she was terrified. It was a rule that the greatest trainer would instruct the crown prince. She couldn't take it anymore because her son was the next emperor. As a result, she dismissed Alfred as Richard's trainer.

Alfred and Richard, on the contrary, kept a strong bond. Alfred followed the norms of the kingdom and used to train Richard in secret. Richard had the authority to do so as the crown prince.