Does Atakhan kill Ruin Runner if that's the only unit and Atakhan attacks?

Question

Accepted Answer

Yes, **Atakhan** will force the controller of **Ruin Runner** to kill it if it is the only unit at the battlefield being attacked.

### Why this interaction works:
*   **Atakhan's Ability:** Atakhan's "When I attack" ability reads: *"the defender must kill one of their units here."* This is a forced action imposed on the defending player.
*   **No Targeting:** As established in **RiftJudge FAQ #8755**, this ability does not "choose" or "target" a unit. Instead, it forces the defending player to perform the action of killing one of their own units.
*   **Ruin Runner's Protection:** Ruin Runner's ability ("I can't be chosen by enemy spells and abilities") only protects it from effects that require an opponent to specifically target or choose it. Because Atakhan's ability does not target, it bypasses Ruin Runner's protection.
*   **Mandatory Action:** Since the ability is mandatory and Ruin Runner is the only unit available to satisfy the requirement, the defending player must kill it.

This is consistent with the ruling for **Cull the Weak** (RiftJudge FAQ #8681), which also forces a player to kill a unit they control without targeting, thereby bypassing Ruin Runner's protection.