The Gray Prince

I'm listing this now because if you do not complete it before the Arena line of quests, you'll never get the chance again afterwards.

Contrary to popular belief, you do not have to be the Champion or even a combatant to complete this quest. I have not joined the Arena and managed to complete it just fine.

Fast-travel to the Imperial City Arena.

Go forward, turn left and go down the stairs to the Bloodworks. Proceed until you see a gray orc. Talk to him and go through the story to learn that he's only half-orc, and there's a long story about his orc mother's relationship with a Lord. He'll give you a key to a fortress called Crowhaven and tell you that he was told that the 'secret' to his past is there.

Open your world map and scroll over to Anvil. To its northwest is Crowhaven, so fast-travel to Anvil and head on over.

Go on inside.

Go forward and down some stairs. Kill any wolves you might find, and then continue forward and make a left. Continue straight and make a right. Continue straight through a doorway and then make a left, and another left. Then a right, and go straight until you hit a wall, then another left.

Now go up the stairs to the gate. Once inside, turn left and then right. Go through an old wooden door. Go straight until you hit a wall, then turn left and make your first available right. You'll see stairs, so go up them and through the door.

Turn left, and keep going until you hit a wall. Turn right and right again, and go down some stairs. Go straight until you hit a wall, then turn left and go up the stairs.

Turn left and go straight until Lord Lovidicus (the Gray Prince's father) attacks you. Kill him. Nothing on his body. Hrmmm...

Just past the desk with the chest on it is a room with a desk. There's a diary on it, so read it.

It seems that Lovidicus was a vampire, and goes on about his beloved orc. He never told her about this until she was pregnant. And then she locked him in Crowhaven. The entries go on about his ranting about how evil she was. Then they turned to gibberish--he went mad from hunger.

Take the diary. It is the proof needed. Now go back to talk to the Gray Prince.

He'll reward you before reading it. It's a permanent +3 to Blade, Block, and Athletics.

Then he gets all depressed about things and thinks of himself as a monster.