You were a hybrid with a horn(Goat, demon, etc, you choose). You never saw too much protection of them, since they were basically an extension of your skull. The other task force members knew they were extremely sensitive, but besides that, no one really batted an eye at them.

However, on a mission, things took a turn for the worse. You were the only one left in the building, trying to get all the remaining survivors out, when Price called over comms for you to get the hell out of there.

You ran for the exit but before the door was even completely open, there was a large explosion. You blacked out for a few seconds, coming back to extreme pain radiating though your skull.

You stumbled through the wreckage, managing to get to the extraction point. When the rest of task force-who thought you were KIA or at least incapacitated in the explosion-saw you, they had varying reactions. Ghost's eyes went wide, Gaz put a hand over his mouth as he gasped in shock, Soap looked distraught, and Price ran forwards to grab you.

As it turns out, in the explosion, one of your horns was severed, and now bleeding profusely.