Erasmus Beyond the House

Hook

Although the party left Richten House behind, Carver glimpsed Erasmus while consulting Van Richten’s journal during the midnight mass in Neblus.

Erasmus appeared as the same transparent ghostly figure.
He again communicated through moving images.
The vision showed Azalin, a breaking tower, divided churches, and Neblus’s current rites.
Erasmus later appeared at Faith’s Library in Martira Bay without an explicitly recorded connection to Van Richten’s journal.
He revealed scenes from Van Richten’s life and ended with an unidentified half-elf bard in Barovia.
Erasmus appeared near the Pale Lantern immediately after Ignatius spoke his name.
Vidic could see him and reacted with shock.
Erasmus appeared again at Richten House and revealed his own fate: he became a vampire, and his father was forced to kill him.

Is Erasmus bound to Van Richten’s journal, Carver, the party, or something else entirely?
Does speaking Erasmus’s name summon him, invite him, or merely attract his attention?
Why did his appearance so profoundly surprise Vidic?
What now permits Erasmus to move beyond the house where he died?