You can mod it in. Don't think it's possible to get it in a normal game. 

<Mount_AshwakeDragon> is the name. Lots of ways to get it into the game (quests etc.), but that mount is ridiculously powerful. (+20 attack, fire breath etc.)

Yes. But Blood curse is rather rare to get. The AI's usually clean the Imperium wildlands for loot pretty fast at higher levels. 

You can cheat it for yourself.

Press Ctrl+J to give your sovereign all mounts (including the dragon)

Of course this only works if you add

"-cheats"

in your launch options.