With this build you are trying to set up kills for your team. Unlike other builds for Dehaka you are trying to gank heroes rather then tank them. The goal of this build is to drag enemies as far from the fight as possible. You can run right in the middle of them and just drag one out, because you are so tanky. Use your essence collection as needed to stay alive in fights, but don't spam it. Prioritize Assassins. You want to drag your opponents as far as possible, so prioritize move speed and drag. Dehaka does not do a lot of damage, so don't be very greedy and don't grab someone without some form of dps with you or the enemy is at low life.

In the early game you want to be ready to go anywhere so you can help your team get a pick off. Your team should always be able to get first blood, because enemies are unprepared for someone to jump out of the bush without warning and without any glimmer(Invis) or seeing heroes go in there.
This build is not a build for being the biggest tank or the most kills. If you like having lots of assists and winning games this build is really good. You are trying to get pick offs by pulling enemies out of positions similar to Sylvanas Mind Control.
(Reference from DOTA 2 Bat Rider)

This build could probably be tweaked a bit, but it seems to do pretty good as of now.

I have been trying to figure out what heroes pair well with Dehaka. It seems as if Illidan and other single target dps is really good. LiMing and Jaina are exceptional as well.

I still have not found any major threats to Dehaka, but heroes with stuns can burst you out of your drag.

This ability gives you more move speed which allows you to drag enemies farther, setting your team up for easy picks. (i might switch this for primal aggression, but with this build move speed is important)

You do not need to collect a lot of essence fast, so the last two abilities are out. You will get enough just by moving around the map with your global teleport. Between the other 2 its debatable, but i have found that gaining the stealth is quite useful, plus it can set up for drags.

This is kind of self explanatory. You want to drag people as far out of position as possible. The cool down ability is nice, but you probably will not need to use it twice in a fight. (could be changed though)

A SILENCE!!!! Need I say more. You already get a lot of health regeneration from essence, and a silence is always good. Look at Sylvanas.

You want to teleport in drag someone out of position and get the kill. This gives you more move speed after you teleport, so you can go up and get the drag off easier. You could also go Swift Pursuit, but your probably already teleporting into the brush already.

Either or is good. Elongated Tongue makes it easier to get the drags off, but paralyzing enzymes makes it so your team has more time to get the kill off. I went with elongated tongue because your team should be able to get the kill before your drag ends.

More Silence!!!!! Apex Predator could also be used if your team needs you to move around the map more.