Multiple Personalities Support Group
Dissociative identity disorder is a diagnosis described as the existence in an individual of two or more distinct identities or personalities, each with its own pattern of perceiving and interacting with the environment. At least two of these personalities are considered to routinely take control of the individual's behavior, and there is also some associated memory loss,...

The integration went as expected, oddly enough the original became very dominant and protective once their personalities blended.
For about five minutes.
Then the protector's memories started resurfacing. The protector was used to his trauma, the original... Not so much.
He was basically completely out of it for an hour, then surprise! The flashbacks and sudden memories forced the protector to resurface. Turns out the protector was sort of going dormant because the original (not the host) was feeling safe for the first time in years, so he wasn't really "gone", just "asleep", until his own memories caused the original to need him again.
Just goes to show you can't always predict how the mind works I suppose.
Thank you to everyone who's posted and read this, it helped a lot to write all this out.