Thalios searched for the crack in the ground for what felt like eternity as he scoured Elysium, and finally bore fruit for his labor. Drawn to the darkest of shadows he found the vent in the stone that led to the darkest of prisons ever made. 
But the sound of a chariot brought to him the grim truth that he had been right. The old gods had come to finish them. Thalios whispered his love to Phobetor and Nephthys while he rose to meet his foes.
Set and Horus descended on him in a rage unlike anything a mortal could express. Anger spawned from eternity of life.
Thalios could not spit upon them in his form but imagined doing so anyways. "Uncles. So great to see you. But I'm busy." Thalios' staff whipped side to side to deflect both crossbow bolts. His mother would be saddened to learn he must kill these two but such was the way. Mother never did care for her over reaching siblings. 

The chariots fired off 2 more bolts each as they approached the lone god, Thalios hadn't bothered to move from his position even as his uncles thundered in with weapons drawn. Funny thing about being free to control shadows, Thalios mused.
The ground below detonated in a river of writing pitch black tendrils, smashing the chariots to kindling even as Horus and Set screamed in futility. 
Shadows were not limited to the surface of the stone and earth. The darkness existed anywhere light was not.. Thalios thought of Rhona for a brief moment but disposed of the idea the moment it had come.
Both the gods fought the writhing darkness with tooth, claw, sceptre and beak, the winds rushed in to slice the shadows to no effect. The darkess was all consuming here in the underworld, the blackest reaches of this plane had come to return what someone had stolen. Tartarus was not a sentient place but Thalios swore he could feel the shadows he pulled from that place demanding these two to return. But it spoke of other gods attacking the dead realms.

Thalios turned his gruesome face to watch the two struggle. "Have a good home coming." At his mental command the shadows sunk deep back into the ground dragging their new captive.

Whatever had gotten them out before would do so again if he killed them or imprisoned them. So trapping them was the most effective way to buy time.
Without a delay the Nightmare god Thalios erupted into purple flame as his form was burned to cinders and transported through the various realms to a place he rarely bothered to go.
The Egyptian underworld ruled by Alec.
A plume of smoke announced his arrival into chaos as the scene unfolded. Thousands of undead swarmed the various armored creatures that defended their home as Alec fought two other gods.