D&D 5E Question about Necromancer's "Grim Harvest"

[Gwarok]

Ok, so I was wondering if the creatures killed by the undead made by a Necromancer activate Grim Harvest.

"Once per turn when you kill one or more creatures with a spell of first level or higher, you regain hit points..."

I never thought about it before but it doesn't specify that it has to be a spell you cast directly on them or even that round, so I thought maybe this lets their minions heal them. Anyone asked or answered this?

 

[The Crimson Binome]

A skeleton isn't a spell you cast. If you cast Animate Dead, the effect is just to create a skeleton. Anything that the skeleton does is a non-magical action.

Even if you disintegrate a pillar and cause a rock slide that kills someone, they weren't killed with the spell. I can't imagine how you would kill someone with a spell, without actually affecting them directly. It would work with Cloudkill, though, which isn't necessarily cast on them (if they enter it later) or on the same round (if they die at some point during the duration).

 

[Satyrn]

A skeleton isn't a spell you cast. If you cast Animate Dead, the effect is just to create a skeleton. Anything that the skeleton does is a non-magical action.

Even if you disintegrate a pillar and cause a rock slide that kills someone, they weren't killed with the spell. I can't imagine how you would kill someone with a spell, without actually affecting them directly. It would work with Cloudkill, though, which isn't necessarily cast on them (if they enter it later) or on the same round (if they die at some point during the duration).

Yeah, this.