If you are facing a legendary dragon, try to avoid having either you or him with your back on a wall. Sometimes it can happen that the deathmove freezes you both. Vampire's eyes sometimes glitch and look as if they are always closed, but only if you use a mod that influence how the eyes look/act. If you have dragonborn DLC, check skyrim nexus for a mod called Dragon fast travel. It makes so when you use fast travel when you mount a dragon, you actually see the dragon bringing you to the selected destination. If you play as a werewolf or vampire, I would suggest not using the shouts. Personally, they make me feel as if I'm cheating someone. Also, as you have technically the soul of an immortal dragon, shouldn't you be immortal as well? If I remember correctly, there are two other dovahkiin that we know of: Talos of Atmora and the one found in Dragonborn DLC (forgot the name). Talos is said to have become a God, while the other is still alive to fight you in the DLC. Does that mean they are immortal, or at least never aging?