Mercenary: Ethereal

 is a challenge in Risk of Rain 2

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

Tips

 * Try to destroy time crystals by reducing their health enough for Eviscerate to finish it off so no damage will be incurred from the resulting explosion while in the animation.
 * Drones and turrents can serve as distractions for enemies, allowing one to use Blinding Assault or Eviscerate 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 turrents 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 (Lens-Maker's Glasses, Shaped Glass, etc.) or adding effects that can help in fleeing (Hardlight Afterburner, Energy Drink, etc.) without having to worry about the item being different.
 * Ranged attacks are especially useful in attempting Ethereal. Finding something like a Disposable Missile Launcher or a Royal Capacitator can improve the chances of success. However, this is limited by the generated seed that keeps item spawns static.
 * Shaped Glass does not void the challenge for some reason as you technically do not lose health, but rather 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.