The Adventurer's Guild Vice Guild Master of the Orinfeld branch, Eldrinia Bronzeblood, a.k.a. Elly, was a dwarf just like Dr. Zellbrook. However, due to the difference in their blood concentration, she exhibited only the stunted growth of dwarves, without the excess facial hairs or the stout figure.
As such, it wasn't weird that Aster would mistake her for a young elf, given her figure and appearance—despite her being 144 years old already. Despite how young she looked, she was way older than Dr. Zell!
"I see... So such a thing happened."
At that moment, Cassy just finished recounting the story she told Zena, with Aster pitching in a few more details as the one who directly fought the monster and defeated it.
"Immune to all attacks, has a reflection skill, and doesn't give experience when defeated..." She muttered with a complicated expression. "This... sounds like a ghost-type monster."