If one thought about it, this definition sounded strikingly similar to Ryu's own and there was indeed quite a bit of overlap. This was simply how real life was… the true state of nature and the universe always had redundancies.
But, even though the two pairs of Pupils shared some basic abilities, as they evolved, they would only continue to diverge.
If one main difference had to be stated between the two now, it could be said that while Ryu had to deduce the truth, Sarriel was enlightened about the truth. Though similar, they were functionally different.
Ryu had to deduce Sarriel's age by measuring her vitality and using his experience to compare her to others. But, if Sarriel wanted to know his age, it would practically appear like a number branded to his forehead for her.
But, this was only one half of the Truth Pupils… Truth meant more than just seeing through to the reality… It also meant assigning Truth as well.