Hunted Demons Forge

"Life Support" - "Adventure Mode - Revive your fallen companion 20 times during the game"

For those who play through solo, you will notice that your AI partner does not go down very often and certainly not the 20 times required for this achievement (maybe 2-3 times during 2 full runs for me).

A solution for this is to switch on a second controller and play through a boss fight several times in split screen mode allowing your partner to simply die over and over again. You will need to get to the end of the fight to allow the game to checkpoint and save your progress. I therefore suggest that you start taking an active role in proceedings once you are down to a single resurrection phial to avoid any wasted effort.

Good locations for this method are Section 1.6 and Section 3.6.

If you play through the game solo on Casual chances are your partner isn't going to die much, if at all. But you can boost this achievement with a second controller as JernauGurgeh SF also states.

I think an easier way to do this, however, is to load up Chapter 1.2. Upon starting run with your primary character past the prisoner and ahead to the cutscene (this will also warp your second character right next to you).

Then run forward into the house with your primary character, kill the shuffling wargar and turn left around the corner where he come from. There is a revive vial here that you'll need to grab every time. Run up to the second floor and kill the two wargar there, then run out to the balcony and kill all of the wargar in the courtyard. Blow up the building across the way and leave your character on the balcony.

Move your other character up through the house, drop down into the courtyard, run over to the three explosive barrels lined up on the left side and smash them with your sword. Boom, dead.

Switch to your primary character and throw the revive vial, then drop into the courtyard and run across the way to the house you just exploded previously. There is another revive vial on the floor here at the foot of the stairs. Run back out and switch controllers.

Smash one of the two remaining explosive barrels in the courtyard with your second character. If you are trying this after maxing out your health and you're playing on casual you will have to smash both barrels to kill yourself.

Switch to your primary character, throw your partner another revive vial, run up through the house killing a few more wargar and initiate the B button partner jump. You can press B a few times to initiate a warp sequence for the second controller. Drop down, make a comment about the dog in the distance while the autosave does its thing, and quit to the main menu.

Rinse and repeat 10 times and the achievement is yours! Mine popped at 19. Also, I've heard of other achievements designated for Adventure Mode popping in Crucible, but I can confirm that this does not work for Life Support.