During their talk, Jason found out that the two of them would only stay on Astrix until Seron´s second soulbond would hatch, which was roughly 4-6 months from now.
Until then, both of them would stay in Cyro-City and play teacher and student, while Seron would improve his strength and mana core rank.
Mr.Greil would most likely just continue playing a teacher because he asked Jason to keep their identity a secret.
Jason didn't mind that and getting to know how long the two of them would stay on Astrix gave him the chance to receive more benefits from them.
Considering the fact that he had already received a unique skill that was more difficult to obtain than most tier-3 techniques and was equivalent to Blessed Skills without much effort made Jason eager to learn more.