So...I've named my little fawn Ohn and come up with a bit of a story for him:

Ohn woke up in the forest, alone, and with no knowledge of who/what he was or where he'd been before then. At first he wandered aimlessly, searching for someone...he didn't even know who it was he was looking for.

After weeks of this he begins to get a sense of himself. He recognizes that the strange glowing sigil over his head is His sign, and names himself Ohn as the main body of the sigil is a large O. Eventually he notices that there are other deer that have very similar sigils, always with a large O and then some superfluous designs around it. Because the base of these sigils are the same, he begins to view it as something of a surname...and convinces himself that these other "O's" are the someones he's been searching for....and so, Ohn spends his days searching the forest for more of his "kin", deer he's come to call The House of O.

Now, obviously, who am I to say that these deer are actually related....but Ohn believes they are, and will follow them around. To him, fawns with the sigil are likely brothers/sisters/cousins, while the adults could be mothers/fathers/aunts or uncles. He has no way of asking them if this is true, so he just assumes it is and keeps close to them (particularly the adults, as a young orphaned fawn is likely to attach itself to adults for security) So, if you have an O-bases sigil, and Ohn is running around, don't be surprised if he follows you about for quite awhile.