How to defeat Diablo as a Demon Hunter?

I was inspired by this question that helped me get to Diablo.

How to defeat Rakanoth as a Demon Hunter?

But now I am having trouble beating Diablo himself. I can beat the first one, with the help of health pools. I then can kick the snot out of myself in like 2-3 hits. But I can not beat Shadow Diablo.

Can't use the Templar which had been a big help.

I just did something I said I wouldn't do. I broke down and brought a chest armor with +20 to all resistance and still I can not win.

Edit to the correct amount

I currently do about 1893.35 DPS and have about a 12,122 hp, with +10 life per sec. 1483 armor

I am on Nightmare difficulty. I just reached level 51.

Any suggestions on a build and skills? Should I do more act3/4 clears to get to a certain level for a certain skill?

UPDATE I am moving on to Hell

Thank you all for your help. I gave most of you a vote up, but I am only allowed to give one correct answer.

I tried Ben's Answer first, and I died 4 times before moving on. While it further progressed me, shadow me was too strong and killed me either the first or second time.

I tried yx's suggestion twice next. I never got away from Diablo and he was very hard to kite.

I tried Stephen's suggestion next. The first time I messed up which button was which and Vaulted right into a cage (actually I was just outside but it still stunned me). The second time, I whooped butt finally. The Vaulting helped. The Preparation with Battle Scars was useful in the shadow world, it was like an additional health position.

I am sure ayckoster's suggestion would have also worked. In fact if you take Stephen's answer and replace Entangle with Hunger Arrow, that may help with Hatred regeneration and still hit from off the screen.

I leave this up here for any passersby.

Again thank you all

I defeated Diablo as a L51 Demon Hunter last night, it was a tricky kill, as you correctly point out the Shadow Realm is one of the harder parts due to the lack of health restore points. Unlike some of my answers which are based on second hand knowledge, this is direct experience. Your milage may vary :)

Here is my general build and strategy, I have tried many other things that did not work well.

The key factors here are slowing Diablo down, avoiding damage yourself and finding ways to recover health as you go.

I'm using dexterity to help with damage (943% increase due to dex), 2k armor and 4k dps overall with bonuses included.

Slowing

For my primary damage dealing I chose to use rapid fire with web shot. This skill plays well with +Life on Hit and with Life Steal. Also having some +Hatred Regeneration equipment helped keep this going as long as possible. I also use a Raven Companion for a little supplementary damage and regeneration.

I chose entangling shot due to its hatred regeneration. You can choose to use the heavy burden rune to increase the slowing time as I did or you can use justice is served to recover hatred more quickly and switch back to rapid fire.

Avoiding Damage

It should be needless to say but you should be kiting quite handily by A4 NM. In order to keep kiting Diablo you need to slow him down.

I've been using a shield to help bump my armor numbers up but the block and dodge bonuses I received were really the saving grace. I have around 100 fire/lightning resist and around 50 in the rest (not astronomical numbers but every bit is helping). I found that in the main world fights that the lightning/fire burst could quickly drop me but it was usually his circle of fire that hit me hard. To avoid these sudden situations I found that Vault with the Rattling Roll rune was invaluable. Not only could I survive at close range until an attack was imminent, but I could leap directly towards Diablo and add some stun in. I also used this to avoid the bone cages. If I found that I needed to run, I could easily follow up with a Smoke Screen with the Lingering Fog rune after he shook off stun.

In the Shadow Realm I found that if I waited until my clone was just spawning and hit Smoke Screen I could usually wipe him out with Rapid Fire, hit Smoke Screen again, collect the health globe and reposition for Shadow Diablo very effectively. Oddly I found my clone dealt far more damage than Shadow Diablo, especially when being effective at kiting.

Recovering Health

For the shadow realm this is tricky. As I pointed out above, you can use vault with stunning and smoke screen to get you to the dropped health globes, if you have any equipment buffing the health bonus from that, great. I have a base of about 12,000 hp to work with, and I use +Life on Hit (~100) and some %Damage to Life (3%) to keep myself going. I also regenerate about 100 Life/Second. With this setup I can run away, heal a little, throw some quick shots in and slowly heal myself back up.

I also made sure to equip some resplendent health potions (6500 life). Some times that extra 2k kick over heroic potions made the difference. For emergencies I also kept Preparation with Battle Scars available, a missed vault or smoke screen with low health can be fatal. When I started scrambling away I'd rather hit vault a couple of times, preparation and then smoke screen to get out of harm's way.

I used the Cull the Weak, Sharpshooter and Archery passive skills to add some kick my attacks and the were noticeably helpful.

Using this setup it took me 2 tries to kill Diablo and the 2nd try went very smoothly.

Here are some general tips I have with my DH, I can't go into specifics without knowing exactly what makes him hard for you:

First, my build for boss fights:

• Hungering Arrow (Puncturing Arrow)
• Cluster Arrow (Cluster Bombs)
• Shadow Power (Gloom)
• Preparation (Backup Plan)
• Marked for Death (Mortal Enemy)
• Caltrops (Bait the Trap)
• Sharpshooter
• Archery
• Grenadier

The idea behind this build:

Since boss fights are extremely long you'll need more survivability than the short period smoke screen that typically gets you through the other 99% of the game. Shadow Power is a great ability that allows you to drain life and take drastically reduced damage for long periods of time. I like to use cluster arrow as my spike damage (when I know the boss will stand still for a few seconds), and this build is designed to maximize that damage in short periods of time.

Don't forget to stand in your caltrops. It does two things, provide more crit chance for more damage, and also snares him a little bit for you to get away should he rush up to you. Not too useful on diablo, but great on bosses like butcher and izual.

Here are some things I do specifically against Diablo:

1. Watch out for the inky spots on the ground. When you see those, start running around like mad. If he catches you in the bone cage you are most likely done for (unless you get lucky and activate shadow power right before you get trapped. Unlike most jails in the game, you can't use any abilities while in that bone cage, which sucks.

2. Stay out of his big ground aoe effect. Pretty much a no brainer, if he uses it, pop shadow power and run out of it before fighting.

3. In the shadow realm, make sure you take care of your own shadow first just to keep the damage lower.

4. In the third stage, watch out for the lightning blast, make sure you kite around him in circles (don't forget to shoot every once in a while) to make him miss his lightning as he rotates fairly slowly.

5. I can't stress this enough, always pay attention to the ground underneath you and avoid the inky spots at all times to avoid being trapped.

Having said all that, Diablo 3 is all about getting equipment, if your equipment is bad then there's really not much that can be done to help you. Also, 1300 dps is a bit low for a level 51, try investing in a better bow and/or more dex or + damage gear.

From Zrie's answer in the Rakanoth thread, be cheap and stun him like crazy. With this method, I was able to easily solo him in Nightmare with terrible gear (1200 dps and 7k health at level 51). First off, the other answers are definitely true. You need to know the mechanics so you don't get hit and leveling or getting better gear will help. Note that this method works even better if you have a freeze or stun effect on your gear (I had 2% freeze and 1% stun). Now for the build and specific strategy (using elective mode of course):

Abilities

Bola Shot: Thundering Rune - Stuns about 30% of the time, used to regen hatred.
Impale: Impact - Stuns him almost every time and does massive damage.
Smoke Screen: Lingering Fog - A necessity to quickly save yourself from whatever you're about to get hit by (except the cages, although it can help to run away from them if you're using Tactical Advantage).
Preparation: Focused Mind - Lets you essentially spam smoke screen for a good 5-6 or more times every 45 seconds.
Companion: Bat - Regenerates hatred.
Marked for Death: Mortal Enemy - Your attacks do more damage and regenerate hatred.

Passives:

Tactical Advantage - Speedy fast getaways when using Smoke Screen.
Sharpshooter - More damage if you keep your distance.
Archery - No brainer...

Strategy

Start off the fight by throwing an Impale at him and laugh at how he's immediately stunned. Use that time to throw up your Mark of Death (be sure to keep it up the whole fight). Now, alternate your primary and secondary abilities. I was usually able to get off 2-3 Bola Shots, then throw an impale and move away from him while he was stunned. Every now and then he'll get stunned by the Bolas and you can use that extra time to get some more damage in. Count on Impale to stun him, but be ready with a Smoke Screen in case it doesn't. Always keep enough Hatred for at least one Impale and always keep enough Discipline for a Smoke Screen. When Preparation is up, you can go crazy on him for about 15 seconds and just stand there until he's right next to you before you Smoke Screen away. Once it stops regenerating Discipline (make sure you keep enough just in case!), you can be cautious and keep a far distance from him and just use Impale until Prep is back up. If you're a large distance from him, he tends to not do any abilities except the occasional teleport and swing (which is why you keep one SS available). If you want to be really cautious, you can just stay on the complete opposite side of the map until Preparation is back up. For cages, you can either spend your time just watching the ground and moving away from the spots or you can move away and quickly throw an Impale at him to get him to stop casting it. For the 360 degree fireball, you can avoid these easily if you keep your distance. Always have health potions ready and don't be afraid to make a quick getaway to a health well. This strategy works in the last phase as well.

Now for Shadow Diablo...The same strategy applies to Diablo in the Shadow realm, but you need to be extra cautious. He tends to always be near you, so you make good use of Smoke Screen and constant movement. I found that if you keep a sizable distance and stun the crap out of him, you can take big chunks at a time. While Preparation is down, you pretty much move constantly and only throw Impales when he's about to hit you. When the add spawns, obviously he hurts. To counter this, if you always try to keep enough Discipline for at least one SS (preferably two just for this case), when the add spawns you can SS and spam Impale until it's dead. If you use two Smoke Screens, you're guaranteed to not get hit by the add, but one coupled with all the Impale stuns tend to be enough.

The main thing here is patience. As soon as you try to do too much at once, you're going to get shafted. Keep your distance, wait for your own favorable conditions to attack, and don't take stupid chances. This fight took me close to 10 minutes once I did it correctly, and I barely got touched.