There’s a thing in Mystara where Half Elves are like mules in that the human and elven genetics are not entirely compatible. If a Human and an Elf have a child, the offspring is either fundamentally human or Elven, but has some of the cosmetic features of both parent.  Like a human with pointed ears, or an elf that can grow a beard. The ‘elvenness’ is carried along the female line but the human gene is dominant. A family with elves and humans intermixing will have many variations for each family member on how elven or human they look and will have a high number of still-born children. There are very few half-elven people in Mystara and they are a unique race, created by the Immortals, and come from only one region. All this means that Hacklore thinks he is a human with elven features, like pointy ears and he has a slight build. Hacklore is using the Magic-User Class.