Apocalypse

It seems like there are a few dialogue trees here. Beating him up is NOT the only one that works. I am going to try them and write them down here, for science.

So you hunt the Dark Riders as well? Long have I searched for a way to rid Duskwood of their curse, but now it looks like I have become the hunted.

Though we may share an immediate goal, the sins you bear plainly show me that I cannot aid your cause. The Light is not well served by taking power from evil only to give it to evil.

1. The power would serve to defeat the Legion. You consider that an evil goal?
2. 
   
3. I don't have time for your nonsense, priest! The Burning Legion is the greater threat!
4. 
   
5. If you will not tell me, I will strip the answers from your soul! <Attack>

Choose 1:

I will admit that the Legion is a great threat, but my duty is to the Light.

I must stand vigilant against its enemies at all times, no matter how dire the situation appears.

Choose 2:

To me, there is no greater threat than those who despoil the Light!

I will not guide the hand of a sinner to power, no matter the ultimate cost!

Either way, you get the same two options on how to proceed. For ease, let's call them A and B.

• 
  
• A. If we do not act, Sargeras will take this world. There will be no remnant of your Holy Light to follow. Where will your duty be then?
• 
  
• B. Forget this. I will take the answers I need! <Attack>
• 
  

Choose A:

The Light will not falter so long as the brave hold it in their heart. We have seen it guide the Legion’s defeat before, and we will see it again.

And you get three more options, here numbered I, II, and III.

• 
  
• I. You are wrong. I was at the Broken Shore. I saw the demons cut through our men, holy and unholy alike. If we cannot turn the tide now, we are all lost.
• 
  
• II. I saw your holy warriors broken on the rocks outside the Tomb of Sargeras! This is unlike any Legion force we've seen, and we'll need more than your Holy Light to drive it back this time!
• 
  
• III. Enough of this! You will answer me or die, priest! <Attack>
• 
  

Choose either I or II, and Revil is convinced:

Your words are acid, but there is truth in them. Though I detest the methods you employ, it seems we may have no choice.

Very well. I will tell you what I know.

Or you could just kick his ass by choosing any of the <Attack> branches. Either works.

If you manage to kill him with a large burst of damage after choosing option 3 (attack), you will need to wait quite some time for him to respawn. You'll still see him inside the house, but going inside will cause him to vanish. I waited about 5 minutes inside and he appeared again, letting me try again. Go slow while attacking, or if you are reading this from a future expansion, you should probably pick the talking options.

The Karazhan portal is inside the building at the center of Dalaran.
There's a circle thingy at its center that you can step on, which teleports you to a room with a lot of portals.