Fun fact: Aergar would've been giggling to himself for a long time if Fritz had accepted his "quest" because he made it up on the spot. No such vaguely mentioned tree exists, to his knowledge anyway. 

If we want to spin off the idea of Fritz being an alchemist, perhaps that is his purpose or destiny. I don't know if you had something else in mind for him, but he is apparently supposed to be some kind of turning point in history here, and he is already quite the scientist. I don't know if, being human, he would be able to learn magic from Ada, but alchemy is more of a science and while an alchemist cannot always be a magician they can still use magical elements. I mean, I guess that depends on how we would define an alchemist in the context of this world. It's kind of a vague term, I was thinking someone who is like a scientist/chemist because that's what ancient alchemists (in our history) were, but with a lot more mystical/magical elements sorta thrown in there given the context of this world. They'd be scholarly and intelligent, have curious natures, and love to experiment and invent beyond the realm of chemical elements. 

However, if he was going to learn how to be an alchemist, he would need a teacher. I have a character in mind that could work but I want to hear what you guys think.