[Given that Serph does not elaborate on the fact that he is a demon, and that he does not immediately become obviously dangerous, he assumes it's not a matter of immediate concern. Still, the claim is bizarre, that he is a demon that looks like an angel but is also a human.]

An-an alchemist is a scientist that studies alchemy. The study of the material construction of the universe, particularly in regard to the magic of transmutation.

[He resumes moving the container to the oasis and filling it, the shock of Serph's statement of what he is having caused him to briefly stop.]

May I in turn ask what you mean by demon, Serph?