Mercenary: Ethereal

 is a challenge in Risk of Rain 2. It is completed as by completing a Prismatic Trial without falling below 100% Health.

Losing any health or shield invalidates the challenge. Losing Barrier (for example, from ) does not invalidate it.

Tips

 * Try to destroy time crystals by reducing their health enough for or  to finish it off so no damage will be incurred from the resulting explosion while in the animation.
 * Drones and turrets can serve as distractions for enemies, allowing one to use or  to either finish off or soften enemies without risking being hit.
 * All interactables are in the exact location when you initially fail doing the challenge, making it useful for finding drones and turrets to help distract and kill enemies.
 * Items in chests are static in the trial, meaning the spawned item from a certain chest or lunar pod will never change when retrying a trial. This is useful for finding items that can prove to be helpful in dealing more damage (, Shaped Glass, etc.) or adding effects that can help in fleeing (,, etc.) without having to worry about the item being different.
 * Ranged attacks are especially useful in attempting Ethereal. Finding something like a or a  can improve the chances of success. However, this is limited by the generated seed that keeps item spawns static.
 * does not void the challenge as you technically do not lose health, but rather max health is cut in half. The double damage can prove extremely useful as you are meant to not get hit to begin with, so there are no downsides to this.
 * Runs will have random artifacts active for the generated seed. and/or  are recommended for doing Ethereal due to controlled selection of items and the 500% damage increase, respectively.