A few days ago when Number 105 and Number 115 visited Vincent, they convinced him to give the sapling to the two of them to confirm its effects.
They said that they will volunteer themselves to ensure that whatever they heard in their previous Hunter Group was true…
They will be the first ones to transform!
They were willing to sacrifice themselves to learn the secrets of the Tree of Faith for the future of the Celestial Beings…
Of course, Vincent didn't buy that but he agreed to them anyway. After all, they were the ones who had discovered it and he doesn't have plans to take it away from them.
If it will strengthen them, it will also help him in many ways…
Apparently, they mentioned that once they grow the plant for a little bit more and use its energy on their bodies, they would gain a stronger connection to the Tree of Faith and gain a miraculous transformation so they can start collecting energy from the sun!