I was asked about the specs for this build regarding a post I made a few days ago by the user: u/Infinite\_growth9383. So here it is: In the 1st pic, you have the most essential upgrades for this build. These upgrades will assure that you'll be regenerating health no matter what your doing. In the 2nd pic, you have secondary upgrades which will improve the performance of the first. (E.g.: increase in attack speed will increase your overall healing output.) And finally, in the 3rd Pic, you have additional upgrades which help boost your performance in fighting certain enemies. (E.g.: the upgrade "Cushioned Padding" will give you a -40% negative effect duration boost against heroes like Ashe, who have DOT abilities.)

Note: I've found from personal experience that this is one of the best builds to use for Rienhardt, provided that you play a certain way or build it a certain way, which again will all depend on the team or enemies you encounter. That being said, here are a few pieces of advice for anyone wishing to use this build: 

1: Play with your team. 

2: Stay focused on objectives. 

3: Don't over-extend.

4: Focus on staying alive.

5: Coordinate with your team. (Using comms)

6: Live with honor, die with glory.

A couple extra pieces of advice? Having a pocket healer will make this build much stronger. Also try to wait until the 2nd or 3rd round, or until you lose a round or two before acquiring your Powers, as this will allow you to gauge the enemy's strengths and play styles in addition to having options open for acquiring other builds, as once you acquire Powers, those Powers become locked and then you can't replace them and you get stuck with a build that is not viable for playing against certain enemies.

My "Immortal Crusader" build for Rienhardt.