Okay so when I was messing around on destiny two I noticed that there was a little area in the glade of echoes near where you meet the harpy that is friendly in the O captain mission and that different versions of the sentinel vex spawn. I killed off at least ten "sentinel" goblins and two "sentinel" hydra's. I haven't seen any harpy sentinel or hobgoblin sentinel. Maybe there's another race that we don't know of and maybe this is part of some other element of the game? if anyone has any ideas on the topic please say so..this is interesting.