[Theory] The Letters derived from Yhwach

[XZA]

Basically, this theory is that Yhwach, who has the letter "A" stands for "The All", and he can use all letter powers.

The Stern Ritter have all said

Spoiler

You must be registered for see images

Spoiler

You must be registered for see images

Spoiler

You must be registered for see images

Something along the lines of "His majesty gave me..." or "I was blessed with..." which leads me to believe that they weren't simply born or "unlocked" those powers. Ryuken and Uryu haven't been show to use any power like Fear manipulation or Massacre powerups, however, once he drank that liquid, which I think is Yhwachs blood, he will then get "handed" his powers.

 

[Narutoga]

That is likely to be correct since he created them, he can also erase them from existence when he feels like.
But, what about royd and loyd,(not sure about spelling) ,they were said to have their ability right from when they were born.

 

[Narutoga]

That is likely to be correct since he created them, he can also erase them from existence when he feels like.
But, what about royd and loyd,(not sure about spelling) ,they were said to have their ability right from when they were born.