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 barriers (for example, from ) does not invalidate it.

Tips

 * Try to destroy time crystals by reducing their health enough for or  to destroy them, so that no damage is incurred from the resulting explosion.
 * 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 (,, 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 invalidate the challenge as it is not technically falling below 100% health. Rather, the 100% health value is reduced. The double damage can prove extremely useful; taking any damage fails the challenge anyway, so there are no downsides to doing 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.