Karthus and Mixologist attack into a battlefield. Can Mixologist bring back Karthus?

Question

Accepted Answer

Yes, **Glasc Mixologist** can bring back **Karthus, Eternal** from your trash if they die simultaneously, provided that Karthus's energy cost and requirements are met.

### Sequence of Events
1.  **Simultaneous Death:** When **Glasc Mixologist** and **Karthus, Eternal** take lethal damage at the same time (e.g., from a board-wiping effect or combat), both are marked for death.
2.  **Deathknell Triggers:** According to Rule 808.1.d.2, *Deathknell* triggers are added to the chain as pending items **before** the units are moved to the trash.
3.  **Karthus's Passive:** Because **Karthus, Eternal** was on the battlefield at the exact moment of death, his passive ability ("Your [Deathknell] effects trigger an additional time") applies to the *Deathknell* trigger generated by **Glasc Mixologist**.
4.  **Chain Resolution:** The *Deathknell* triggers enter the chain. You are the controller of the triggers and choose their resolution order.
5.  **Revival:** When you resolve the *Deathknell* effect from **Glasc Mixologist**, you may choose a unit from your trash that meets the requirements (Energy cost 3 or less and [A] or less). Since **Karthus, Eternal** has an energy cost of 3, he is a valid target to be played from the trash to the battlefield.

### Key Considerations
*   **Timing:** Per the *Unleashed* rules update and Rule 187.4.c, you do not lose control of the battlefield while there are pending items on the chain (such as the *Deathknell* trigger). This allows you to play the unit back to the same battlefield where they died.
*   **Karthus's Passive:** It is essential that **Karthus, Eternal** was on the board *before* the *Deathknell* trigger was created. If he were not present (e.g., if he was in the trash already and you were trying to revive him to trigger the double *Deathknell* for the same event), his passive would not apply to that specific trigger (as clarified in **RiftJudge FAQ #9606** and **#9256**).

This is my interpretation based on the mechanics of *Deathknell* timing (Rule 808.1.d.2) and the interaction of passive abilities with battlefield control as established in **RiftJudge FAQ #9316** and **FAQ #9392**.