As soon as the angel of knowledge left, a demigod of knowledge with enough qualifications took over the available spot for an angel and replaced him.
This new angel of knowledge was the one that the possessed first angel of telepathy met when he came to the white tower looking for Legion's identity.
The god of dreams knows a lot about the world and its past due to his access to the dreams of the dream realm, so finding new information to deliver wasn't much of a problem for him.
However, what the god of dreams was asking for was very difficult for the angel of knowledge to solve because the information about Legion didn't fit the description of someone.
This wasn't surprising since Legion was said to be an undying godclad. Undying godclads have their information protected by the Aegis Shield, so they are difficult to find.
