Even if he was the reincarnation of his half-brother, a mere Magical Beast still wasn't enough to kill this hero.
What truly killed him was the "Geis."
Even the Great Hero of Celtic mythology, the Child of Light Cú Chulainn, had only three Geis in his entire life.
Yet the tragic hero, Diarmuid, bore more than ten Geis throughout his life.
Princess Gráinne, daughter of King Cormac, once used a Geis to force Diarmuid to elope with her during her wedding.
This caused a rift between Diarmuid and his lord, Finn MacCool, and forced him to flee for the next sixteen years.
There were many other Geis besides that, such as:
"Never refuse when a companion extends an invitation."
"Must participate in a hunt upon hearing hounds barking."
"Must not hunt boars."
"Will die by a boar."
That's right—
Diarmuid's lord cleverly used these four Geis to orchestrate his murder.
A Geis was an absolutely unavoidable fate. Even the greatest hero could not defy it.
However, because of their absolute binding power and power over fate, Geis could also grant warriors unparalleled strength.
The more Geis one had, the greater the "power" one obtained.
The more contradictory the rules of the Geis, the more terrifying the "power" became.
Diarmuid, who had been bound by Geis all his life, completely abandoned the knight's creed—
Using his hideous boar skin as a symbol, he twisted the power of those Geis into a terrifying demonic nature.
"How could this..."
Saber was utterly stunned.
At the same time, the wound Diarmuid had suffered from Shirou's Reversed Holy Sword had completely healed.
But it looked nothing like healing magecraft. It resembled a Magical Beast's regeneration, just like those tentacled monsters she had slain moments ago.
"Lancer, what are you..."
"His class is still Lancer, but