The goal here is to assist your Battlebuddy, and to help them kills fools.
This isn't a solo DPS Rehgar, and it's not a full support Rehgar, it's an in between. you will be able to support your team with Heals and shields without needing an extra support, but we do it on a budget and try not to spend talent picks on healing.

It's important to note that I only encourage this build when it suits the comp, i.e. when you have a good Battlebuddy.

Your Battlebuddy is a hero that will deal damage, get in people's faces and kill them.
As such you want a Melee Assassin preferably, although the more ddmg oriented tanks are also acceptable.

Possible Candidates for your Battlebuddy:

• Illidan
• Zeratul
• Thrall (Bonus points for Orc Bros)
• Anub'arak
• Kerrigan
• Sonya

Remember that your Lightning Shield lvl 1 talent buffs their AA damage, so the more the are likely to be using their AA to kill enemy heroes the better.

In fights you want to be in there with them, not all the way in, but close enough that if they dive you can still reach them to cast your abilities on them.

In 1v1's you want to get the full use out of both your trait Ghost Wolf, your Lightning Shield, and your Earthbind totem.
Always shield your buddy, use your totem aggressively to lock down their retreat, and use your trait to chase them for the Kill. Remember that your basic attack coming out of ghost Wolf deals double damage, so be sure to use it frequently.

At lvl 1

we take Empowering charge, buffing the shield target's next 3 basic attacks by 25%, allowing them to increase their DPS. Remember that since it's a percentage Heroes with higher AA dmg benefit more from your shield.

At lvl 4

we take feral Heart, this talent makes sure you don't run out of mana as often and just generally keeps you in the fight longer. Which where you need to be.

At lvl 7

we take Earth shield, which confusingly adds a shield to Lightning shield... It provides valuable sustain to your Battlebuddy and yourself if needed, and allows them to be even more aggressive in fights.

Our Heroic

pick will be Ancestral Healing, simply put without it Rehgar as a solo heal wouldn't be sufficient. And again you will usually be casting it on your Battlebuddy, and sometimes your tank, if needed. Timing on it is crucial, and you'll need to practice in order to get the most out of it.

At lvl 13

we have two possible picks. If at this point it becomes clear that your team needs more heals because they are melting in fights, then take Healing Surge, it's a significant buff to your healing potential and is undeniably a strong pick.
On the other hand if your team seems not to need extra healing then we take Stormcaller. This talent cuts your cooldown from 8 to 6, which means Lightning Shield can be cast only 1 second after it has worn off. the mana cost reduction is also huge. And allows you to spam this ability in long fights.

At lvl 16

we take Lightning Bond, doubling the dmg output of Lightning Shield, it also provides you with twice the Shielding. This paired with the reduced cooldown from stormcaller is very strong. And means you will rarely take serious damage in fights.

At lvl 20

we take Farseer's Blessing, which adds an AOE heal to your ult. Stormshield is also an option if your team needs to be more tanky, but I prefer farseer's and Rewind simply isn't needed with a 6 second cooldown on Lightning Shield.