If a nontoken creature that isn't normally a creature (such as a Vehicle) would die, Rayami exiles it with a blood counter on it, although Rayami won't gain any of its abilities.

If an exiled creature card has one of the listed keywords only if certain conditions are met, the ability granting that keyword doesn't apply while the card is in exile. Rayami won't gain that ability from that card.

If an exiled creature card has one or more variants of the listed keywords (for example, protection from black or hexproof from white), Rayami gains those specific variants.

Rayami looks at all exiled creature cards with blood counters, not only those exiled with its ability. It even looks at those exiled by an ability of another player's Rayami, First of the Fallen.

Nontoken creatures that would die at the same time that Rayami leaves the battlefield are exiled with blood counters.

If multiple replacement effects try to change where a dying creature would go, the controller of the creature chooses one to apply. If Rayami's effect doesn't exile the creature, it won't have a blood counter on it, even if another effect exiles it.