High-ranking Magic Knights (mostly from the Golden Dawn) are possessed by elven souls.
It highlights the ultimate betrayal by William Vangeance against the man who raised him. Black Clover (TV) Episode 106
A breakdown of the and which knight hosts which Elf. High-ranking Magic Knights (mostly from the Golden Dawn)
The "Elf-forms" introduce a massive power gap, forcing the remaining human knights to fight for survival rather than just victory. Black Clover (TV) Episode 106
The episode forces the audience to look at through a complex lens. He isn't a traditional villain; he is a man torn between two loyalties. By choosing Patry, he chooses his oldest friend over his kingdom, leading to the near-extinction of the humans he swore to protect.