Are Death Saving throws a cause of death that triggers Finger of Death zombification?

Question

In a followup to this question, I am now asking if Death Saving Throws would be a separate cause of death from Finger of Death(FoD) is the cause of the Character's demise.

Finger of Death has the clause:

A humanoid killed by this spell rises at the start of your next turn as a zombie that is permanently under your command...

Say a character is dropped to 0 hp by Finger of Death and then they fail 3 death saving throws by rolling below 10 three times. Did the character die from failing saving throws, or from FoD? Or does FoD have to kill a character outright (from massive damage) in order to trigger that clause?

Answer 1

No, a rolled death save will not spawn a zombie - Finger of Death can kill in 2 ways

Way 1: Massive Damage

Finger of Death deals damage greater than the targets Current HP+Maximum HP. The target dies instantly from massive damage and rises as a zombie

Way 2: 3rd Failed Death Saving Throw From an FoD hit

The target is unconscious* at 2 failed death saving throws. FoD hits causing an instant failed save (from damage while unconscious). The target dies and rises as a zombie.

Finger of Death is only the (mechanical) cause of death if you die while the action is happening and because of that exact action.

*One possible exception is on a Zealot Barbarian who delays the death due to raging but ends their rage having been hit by FoD on at 2 failed saves. The delay would occur but they would become a zombie as soon as they truly die (If they are still at 0 hp at the end of rage, and have not been healed since FoD "killed" them).

Answer 2

No, a death saving throw cannot trigger finger of death

General case

Whenever you start your turn with 0 hit points, you must make a special saving throw, called a death saving throw, to determine whether you creep closer to death or hang onto life.

[...]

On your third success, you become stable (see below). On your third failure, you die.

Until a creature has failed their last death saving throw, nothing has killed them; they are still "clinging to life". Thus, only an effect that causes you to fail your last death saving throw (or kills you instantly) can be said to have actually killed you.

Jeremy Crawford has also agreed with this:

Q: For Finger of Death: if the spell brings the target to 0hp and the target subsequently dies due to failed death saves, dies that count as FoD killing the target? Will it rise as a zombie?

A: A spell kills you if its damage or other effects slay you. If it reduces you to 0 hit points but leaves you alive, it didn't kill you.

If there is no effect that explicitly caused the final death saving throw to fail (eg damage) then, nothing caused the final death of the creature, only the d20 itself.

Specific case: finger of death

Finger of death says:

A humanoid killed by this spell rises at the start of your next turn as a zombie that is permanently under your command [...]

Thus, only when the spell was the final cause of death of the creature does its effect take place.

So as an example, say finger of death brings a creature down to 0 hp but does not kill them instantly. Then, the as the round proceeds, the character fails three death saving throws below 10. In this case, it does not matter what dropped the creature to 0 hp because none of those things resulted in the character dying. What caused the death was failing the death saving throw. And since nothing caused that death saving throw to automatically fail (or modify it in any way) then no effect can claim to have killed the character. Thus, no effects can trigger off of having killed the creature.

Answer 3

No, because a PC who is dropped to 0 hitpoints is not killed, but unconscious and dying. The Players Handbook takes some pains to distinguish this. Also, Finger of Death has an Instantaneous Duration, while it can take up-to 5 Rounds for a character to finally die.

I am going to paraphrase an answer I made to another question on this same subject.

Death Saving Throws

If damage reduces you to 0 hit points and fails to kill you, you fall Unconscious (see Conditions ). This unconsciousness ends if you regain any hit points.

That itself is pretty-clear: If an attack drops you to 0 hitpoints but doesn't exceed your hitpoint maximum, by RAW it fails to kill you.

Finger of Death

You send negative energy coursing through a creature that you can see within range, causing it searing pain. The target must make a Constitution saving throw. It takes 7d8+30 necrotic damage on a failed save, or half as much damage on a successful one.

A humanoid killed by this spell rises at the start of your next turn as a Zombie that is permanently under your Command, following your verbal orders to the best of its ability.

So, let's look at Mac, a Level 5 Fighter with 44 Hitpoints. Mac, at full health, decides to go bully a high-level Warlock NPC.

The Warlock, not amused at all, casts Finger of Death on Mac, who fails his saving throw and takes 67 (rolling 7d8+30) points of damage. This is enough to send him from 44 to 0, but the damage remaining is 23, which doesn't exceed 44. Therefore, Mac does not die; by RAW, the spell fails to kill him outright, but he is now unconscious.

Now, Finger of Death, an Instantaneous-Duration Spell, works by arcing negative energy through the target. After the spell is over, the negative energy (the same kind of energy which, by D&D official Lore, animates Undead) is no longer coursing through Mac's body. In fact, it has pretty-much dissipated after draining most of his energy. If Mac were to fail his next 3 saving throws, it wouldn't be the spell that killed him: the magic is over and done with. Instead, it is the fact that he can no longer procure enough life energy to continue to beat his heart or breathe which kills him.

That is why Mac would not come back as a Zombie, because there is no negative energy left from the spell to animate him, that expired several turns ago when the spell's duration (Instantaneous) wore-off.