Invincible Dragon?

[MrCostari]

I was doing the main quest and I killed Alduin and after that I was back at the Throat Of The World, a lot of dragons were flying around and nothing happened so I decided to throw a shout into the air and that was Dragonrend. So for some reason I hit Odahhving and he came down to the ground. Now the weird thing comes, I could not damage him, I slashed and stabbed him but nothing happened. So I decided to run away and he chased me. After a short falling of the mountain (which I survived lol) I ended up at High Hrotghar and went inside, and exited at the front door. The dragon was gone and I could fast travel.
But why did this happened? Was this a glitch? Was it random that I hit Odahhving with the Dragonrend?
Was it meant to happen?

 

[shwangu]

its just that Odahhving is a required npc for the shout call dragon so you cant kill him and yes you hit him randomly

 

[MrCostari]

No that's way after that quest lol.

 

[DryadSpeaks]

The shout call dragon stays with you after that quest...

You can use it anytime to call him to help you. That's why he can't be killed.

 

[Squirrel_killer-]

Odahviing is marked as essentially, this makes it impossible for him to die.

 

[MrCostari]

I'm quite sure I used Dragonrend...

 

[DryadSpeaks]

What we're saying is that you probably hit him accidentally with Dragonrend, but be still can't be killed because he is an essential NPC.

 

[MrCostari]

Oh I see. But I couldn't damage him at all? Usually when someone is essential they go on their knees and get back up after a while.