something to keep in mind for my setting.
an Echo is the remnants of magic taking on the patterns of something or someone that is no longer present. It is not a ghost.
a Ghost is a disembodied soul, and may or may not have the mind that it once belonged to attached. Typically, these are incredibly rare, and only appear under certain circumstances, such as someone preventing themself from being taken to the afterlife, or someone being pulled from the afterlife for some purpose.
(note: when not in a simulacrum Erick's technically a ghost, which is why I sometimes refer to him as a "screaming ghost in a body of silicon". the "screaming" part referring to the fact of his sheer arcane power.)