Christ alive, this wasn't a merger, and as far as I know, it wasn't a bug exploit. Some very clever characters presented Malus with a set of facts that, when measured against what he already knew, pointed to an outcome that he found so abhorrent that he abandoned a realm named after himself. This was neither convenient nor easy for me as a player, but it is exactly what the character would have done.
Reads: enterprising individuals fabricated something, and it was believed without a second thought or even a word of it to the people it implicated.