Whisperling

We know that humans exist in all three realms in some capacity, and that everything has a presence in both the physical realm and the cognitive realm. That said, it seems unclear whether things that aren't alive, and therefore ensouled, have any presence or effect on a spiritual level. I could see this being a matter of whether something is Invested or not. Hemalurgic spikes also seem relevant, though that's arguably a bit of a niche case.