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 is an Elf with human features, like smaller ears and he’s very tall (for an elf). Hacklore is using the Elf Mage Class from the Elves of Alfheim even though his magic education is based on his education at Eztar’s School of Magic and not from the Keepers of the Tree of Life.