While adventuring, I was attacked by an Elder Dragon, when I got to my Destination, I landed and I attacked it, with my Dawngaurd War Axe, doing 35 damage, And It was just CHOPPING OFF it's health! I was like Elderdragon; Y U SO WEAK?

I also shouted Marked for Death at it.

Master difficulty?

According to the wiki, sometimes the computer gets confused and names them incorrectly, so your elder dragon may have been a normal dragon. Or it could just be really weak!

Either way, i wish my elder dragons were nice and easy haha! My Blade doing 110 damage and absorbing 18 health still takes a number of swipes to slay things.

It was weak because you used Mark of Death.

Because it's really old dude. Hitting your grand-mother or grand-father would definitely mow them down quickly, compared to say hitting a boxer in his 30's.

Ok, but seriously though. All the dragons are weak in the game. What makes some of them appear stronger than the others is if you have level-appropiate gear or not.
Mark of death does add a nice amount of damage though.

Do you still have fun?

I wouldn't.