I disagree on this one because they count as separate hits for concentration so I'd assume they count as separate hits for Death saves 

You are responding to something from 2 years ago, FYI.
But no, they don't.  Yes, Jeremy Crawford said they do, whereas Mike Mearls said they don't; bottom line, don't take their tweets as concrete rules.

Divine word

As Jaysburn mentioned, there was already disagreement by rules guys on that. But the spell is an AoE spell and states they strike simultaneously. It's the same reason RAW is roll once and apply to all darts.

Just to be clear does this still work if you take double you maximum and instantly die? (I.e you have 100 hit points and take 200 points of damage)

edit: I think it does still work, similar abilities like relentless endurance specifically state that it only works if you are reduced to 0 but not killed outright and death ward does not say that.

Personally I would argue yes. The wording on Massive damage in the PHB states that "When damage reduces you to 0 hitpoints and there is damage remaining". Since a requirement for massive damage killing you is that you drop to 0 hp, I'd say that deathward would proc and reduce you to 1 hp instead

Personally think this works better as a 3rd level spell. I would feel really gross if I burnt a 4th level spell slot that was defeated by multiattack.

This is an incredibly powerful spell.  Instant death is not the same as going down for death saves.

Could you use wish to kill someone and that someone had this spell on him would the spell work

why do only alchemist get it

Quote from Rattleman >>

why do only alchemist get it

 You can still get it via spellwrought tattoo.

Quote from Ropetrick6 >>

Assuming you're not a barbarian, it goes like this: you take 20d6(terminal velocity) damage, and if you have enough levels you might not even drop to 0, and if you're barbarian then it's only 10d6. Then, if you did drop to 0 or below, you instead drop to 1 HP. This even works against instakill damage, as since there isn't negative HP, you can only drop down to 0, which then gets set to 1 because of this spell.

 Should mention that barbarians would take (20d6)/2, not 10d6. There is a difference there. Resistance means they roll the same amount of dice to damage you, you just take half of what the result is, instead of them rolling half the number of dice.

Quote from LightHunter >>

Quote from Kelain >>

Well technically wouldnt disintegrate hitting someone below the minimum damage count?

 The wording for Disintegrate is actually very specific. the spell must "leave the target with zero health" to destroy the body. This gives time for Contingency, deathward to restore the individual. I also Believe the Half-Orc Relentless Endurance would work as it states if the Damage does not kill you out right, you instead go to 1 HP. So you are reduced to zero, you get increased to one, then the Disintegrate checks to see if you have stayed at zero. Since you have increased in HP you are not destroyed.

 There's no way this is true. In this example, I would say Disintegrate kills you outright. No way a half-orc just ensures and shrugs off total disintegration. That would make Relentless Endurance the same as Death Ward, which I do not believe was the intent, based on the different wording.

I would, however, agree that Death Ward would prevent the disintegration insta-kill.

Power word kill

Quote from Richybabes >>

Yes, but multiple instances of it. If you use a 2nd level magic missile Vs 6 hp and roll all 1s, you'll deal 2 damage four times. The third would drop it to zero, but due to death ward instead drop them to 1. The fourth missile will down them.

 No the fourth missile wouldn't down them. The spell specifies that all darts strike their target at the same time. All damage occurs at the same time. Remember that combat is turn based.

Quote from Ropetrick6 >>

... This even works against instakill damage, as since there isn't negative HP, you can only drop down to 0, ...

 If enough damage is dealt to take a character to 0 hp and the excess damage is equal to their max HP, they are killed instantly. 

So there kind of is a negative HP, it is just virtual and only applies if it equals your max HP. This might also qualify as insta-death but probably not, since there is damage dealt.  

Yea

is there no way for a wizard to have this on their list?

Quote from EurekaBe >>

is there no way for a wizard to have this on their list?

 Well, it's not a wizard spell....

Actually, Rules As Written, a Banshee's scream is NOT prevented by Death Ward. This is one case where you are not being 'killed', you are just being reduced to 0 hit points, but you are also not being reduced to 0 hit points 'as a result of taking damage'. A Banshee's wail does not do damage if it reduces a creature to 0, it simply sets their hp at 0. So Death Ward actually cannot protect you from that one.