Dark Knight's fire magic

In Deltarune, the Holiday family is introduced to us as divided between ice (Carol and Noelle) and fire (Rudolf, for now). Since the family consists of four members, it seems clear that to “balance” this disparity (2 ice and 1 fire), Dess must represent fire, just like his father. Therefore, if the Dark Knight were indeed revealed to be Dess, then I’m certain he would have fire magic.