Hewitt left the Pure White Tower.
He could not find any trace of the third Knight Apprentice.
There are three common ways to erase a person's existence.
First, erase their existence and others' memories of them. This is often done by a killer with strong mental abilities or by using forbidden memory-related items.
However, this cannot erase the traces of the person's life, and careful searching will always find gaps. This ability poses no threat to Hewitt.
Second, in addition to erasing others' impressions of them, all items related to them will also disappear. This disappearance is on a material level, and to keep the world running, it may create memories and items that did not previously exist.
If the erased person had a significant impact on others in the past, this impact would still exist, but it would be distorted to other causes.
