You were wrong. You thought you could weather this storm; you knew your father was sick, and it was only a matter of time before the affliction took his life - but even so, he had somehow always seemed... immortal. Marietta looks at you with concern as the two of you clatter down the palace steps. You are glad for her presence, even if she did come too late to save him.
"Will you be king now?" Her voice is soft, nervous. She is probably scared of the idea of that: you, running a kingdom. Goodness knows it scares you just as much.
You open your mouth to answer - yes, you will be king according to the line of succession, but you might appoint Smarmy as a regent for the time being. You are still a young unicorn, and you want to see the world before the weight of a kingdom is thrust upon your (well-muscled) shoulders.
Before you can say as much, however, something crashes behind you, and you hear the rasp of a sword coming free of its sheath. Marietta whirls about, a black light glittering in her eyes and horn. "Humans!" she rasps, and you see them.
Long, hairless animals crouch in the shadoes, blades in their hands, clothed in the pelts of dead unicorns. You are paralyzed by terror; Marietta is not. She screams and rears, hooves flashing dangerously. "Run!"
You run.
Marietta pelts after you, and you race from the palace together, humans falling behind.
A ghost stands outside, covered in white cloth, its eyes red as sunset. They rear as if in salute, and Marietta laughs behind you.
"Hello, ghostie," she says to the strange unicorn. They look affronted. "Smarmy is making a bid for the throne," she pants. "We need to protect the princeling here."
The ghost nods, and its horn glows with terrible power. Flames launch from it, spraying toward the pursuing humans. You watch them die in agony, flesh melting off their bones, skulls grinning under burning eye sockets.
"Let's move," Marietta says, suddenly gentle.