This is another Story of the Exiled Prince, he is the subject of many Fauni tales but in Trystan's time most historical records assume he is dead, others think he is off doing whatever exiled sorcerers do.
You may remember him being mentioned briefly in the first tale I posted years ago, he was the guy who cut off his own Father's head, you can only imagine how he must feel holding his horns in this illustration...awkward.