First, one needs to know more about the animal behavior of the wild ass: It knows no spouse or loyalty and hides from the light (ref "Irad" in Gen. 4:18). Then recall that the root for "hand" (yud dalet) is the same as what it is to "know" or to procreate and can literally mean the male phallus. Ishmael's "face" (panim) means that his FEATURES will be in every man, as he will interbreed with them which is why he dwells in their tents. Remember too that the "angel" of the Lord (you know, the one that Hagar names GOD in v.13) had promised that Ismael's descendants would be a multitude without number in v. 16:10. Yes, IMO, the angel in this story is the Adversary, Ha Satan, who raises up the children of Ishmael because Hagar named him "yud-hey-vav-hey." It is a symmetry with the covenant between G_d and Abraham that is not to be missed.