Question about Mana Tempest / Spark & murderous intend

Running spark with mana tempest on my sorc, and placing murderous intend into mana tempest should make any skill cast while empowered by mana tempest cull enemies.

Additionally, I placed soul drain into spark to recover that sweet 12% mana on culling an enemy, but it doesn't seem to work.

When playing the monk I realized enemies that can be culled by a skill have that little blue flame displayed, which isn't the case with murderous intend and mana tempest.

Wanted to ask if my approach/though is generally not possible or if it's a bug.

Thanks for feedback

Actually I've been trying to get skills to cull that are cast in mana tempest and I am not seeing it work? I used culls to destroy corpses to make sneaky corpse explosion skills less painful.

It might be because the hit is too strong and it dies before it checks to cull? I would have thought that it would cull first if the orb is next to them (I have lightning warp on to check, and the animation from lightning warp is clearly different than spark cast in mana tempest with culling strike).

It is kinda hard to tell, but on bigger enemies it's a bit obvious, and I still am not seeing any automatic culling with mana tempest.

At the very least, it might not give you energy back because you're killing them with an attack before they're culled?