This champion cannot fall below 1 HP and has Skirmisher. While this effect is in play, this champion can not be healed. This unit is destroyed when the effect ends. This effect is hidden until triggered.
Grimlic's Descent Expansion
This spell is similar to Impervious), but in this case the effect is a little different, keeping the champion alive 3 turns instead of 2, and then destroying the champion at the end.