>>725264949
>How?
The Caster in question, Solomon, is the strongest servant in the entire series. I'm not even memeing. He has a pocket dimension he can enter and exit at will, he can see into the future, he can teleport at will, he has attacks that can erase space and time, he has 10 rings that allow him to control and negate ALL mage craft, he can turn off / block all noble phantasms, he vets revelations / divine whispers directly from the nasuverse supreme deity, and he could summon 72 demon pillars each of which is capable of taking on multiple servants. The plot of FGO literally revolves around Goetia, a demon, taking control of Solomon's body after Solomon dies, so that it can all of humanity.
Solomon is so strong that being summoned as a servant is actually a massive NERF for him because no servant container can handle the sheer amount of power that Solomon possessed.