One source I found calls him "the god of hunting, fertility, life and death, a protector and savior often depicted as a riding hunter," In these depictions the hero seems to have his mouth open, which to some scholars implies that he is shouting. Perhaps, they say, Thracian heroes were known for their loud voices or "great war cries" just like the those of the Iliad.
Notice the floating heads, some of humans and some of horses.
one scholar thinks that these are the victims of sacrifice, speaking as they pass through the veil of death. After all one of the purposes of ancient sacrifice, and especially of horse sacrifice, was to obtain prophetic guidance. But you can certainly see that the Thracian hero had a lot of divine help as he went about his adventures. This is one theme of ancient myth that survived into the age of Arthurian knights, who were regularly corrected by wild hermits if they went astray during their journeys: "Galahad you great oaf, you were supposed to look for clues in that castle, not just romance the women!"