>>724859016
>Miquella could've controlled everyone from the beginning
That's not how it works you stupid retard
Miquella can control people without grace by granting them his own rune.
That can't work for Radahn (who is his ally and willingly joins him as Lord) or the player (who is Lord of the Erdtree), but works on Mohg and works on his other NPCs.
This is why the effect of his runes breaks when he discards the Great Rune, but that isn't exclusive to Miquella, controlling people is exactly what grace is for, it's manipulation of light created by the Fingers and the reason as far back as the Nox rebellion mirrorhelms were used to contrast that power.

The only reason the Tarnished can retain some agency is that Marika's grace is fading and won't affect most people now, with a lot of those it used to control now being mindless death after death and seeking to hunt the Tarnished.