There shouldn't be any problems convincing Xanriel and the rest of the Swords. Morte will just treat the Angels, the Masters, and basically all his enemies like they're nothing but ants and garbage. Morte will try to kill every single last one of his enemies, and he will not stop trying unless he is dead or his enemies are all dead. There are no chances, absolutely zero, of Morte turning back to the side of good. Looking at that, I'm sure that the Swords will have no problems killing a corrupt False God like Morte.
Also, we need to kill Morte for the plot development. Malcolm needs to absorb the powers of at least two dead FGs to be strong enough to devour other FGs, otherwise the False Overgod cannot form.
And I might do a bit of the history of the world, in Hell's perspective... Editing in progress.
1) The Elder Days: The age when Zanzarino created the first immortal Higher Beings. Two races of Demons, the Ancient Ones and the Obyriths, formed out of the darkness in the Abyss. The Obyriths, small in number, sought more power by breaching the Outer Gates, absorbing some Void powers into themselves and thus becoming monstrously powerful. A cataclysmic battle resulted, and the Obyriths were sealed away and the Ancient Ones became the dominant force in the Abyss.
2) The First Golden Age: An Ancient One, Bloodshadow, conquers and unites the Demons in the Abyss. The Treaty of Utarius was signed between Heaven, led by Chamuel, and Hell, led by Bloodshadow. Zanzarino, seeing the catastrophic war caused by the Obyriths, decided to appoint a higher order of power in the universe; thus, twelve Elemental Masters were chosen, Bloodshadow and Chamuel among them.
3) The Iron Age: Because the Outer Gates were previously breached by the Obyriths, the powers of the Void began seeping into the universe, and corrupting its denizens. Another great war ensued, which resulted in the extinction of the Ancient Ones. In the end, Zanzarino and the Elemental Masters sacrificed their powers and lives to seal away the Void into several powerful individuals, turning them into False Gods.
4) The Second Golden Age: A newer race of Demons began to populate the Abyss.
5) The Dark Age: One of the Angels, Xanriel, was slain in the Middle Plane, and thus Heaven's powers waned drastically. As a result, massive amounts of less powerful Demons poured out of the Abyss into the Middle Plane. Those who stayed in the Abyss were eventually called True Demons, while those who lived in the Middle Plane became the Lesser Demons.
6) The Last Golden Age: The Lesser Demons, who were running amok in the Middle Plane, were subdued by Heaven. The Lesser Demons congregated with each other, and formed the Kingdom of Darkness.
7) The Age of Independence: Our current time. The Demons and Vampires war over portions of the Kingdom of Darkness, but general order is maintained by Incarnate.