This is considered the most consistent Necrobinder build by the community. Spirit of Ash in an ethereal deck is an automatic win condition.
Game plan
Core three to start: Defy (block + weak, ethereal), Gravewarden (block, puts a Soul in your draw pile), Negative Pulse (AOE doom, block). These three commons alone can carry through Act 1.
Add Spirit of Ash when you see it — it becomes an automatic win in ethereal builds, generating 10-20 block each turn without playing defense cards.
Banshees Cry provides insane upside for ethereal density. Sentry Mode becomes a zero-cost 10 damage 5 block every turn in ethereal decks.
Good signs
Early Defy and Gravewarden appearances, Negative Pulse in first few rewards, and any card that creates ephemeral/ethereal synergies.
Sleight of Flesh is a powerful uncommon pickup — whenever you apply a debuff, the enemy takes 9-13 damage. Combined with Negative Pulse, you get damage on every AOE doom application.