“Ngh...!”
Just as he tried to regain his footing, he was struck by another wild burst of magical energy. Alkeides was not a mage, but as his body was itself a mass of magical energy, every vein and nerve in it could be called a Magic Circuit.
All of them had become fuses and were setting off surges of uncontrolled magical energy one after another in a chain reaction.
Magical energy burst in his lean, steely arms.
Magical energy burst in the toes of his feet, so well-honed that they sometimes became blades.
Magical energy burst in the veins that ran throughout his body, deep and strong as the roots of the world tree.
Magical energy burst in his beautifully woven nerves.
Magical energy burst in each of his alveoli before he even had a chance to breathe.
Magical energy burst behind his eyeballs, hidden by his cloth.
Magical energy burst in a part of his brain stem.
It burst, and burst, and burst...
The interval between bursts of magical energy grew shorter and shorter until at last he felt a massive explosion of magical energy near his heart.
He could not distinguish the pain from the heat of it.
Half of the wings on his back and the horns on his head snapped off. There was even an explosion of magical energy in the hand that held his bow, tearing off several of his thick talons.
The magical energy ran out of control inside his body as well, shredding parts of his organs.
But his Spirit Origin, once renowned as a great hero, was to be feared.
“...No!”
Many Heroic Spirits might have burst entirely at that point, but he had held his body together by the force of his sheer physical strength.

Fate/Strange Fake: Volume 5, Chapter 15 ("Gold & Lions II")