GAC. It is impossible to kill any of the team of SLKR. 1 unit of health remains and they become invulnerable.
Ideas
It is Rey's Malevolent Lineage omicron, in Grand Arena it removes 100% tm from all characters. So some slow characters like kru or red will not get a turn at all. So mirror can work in:
- Other game modes
- If you take not a full team to the battle and only fastest one, like slkr, rey, hux
- If opponent doesn't have this omicron, and if you have it then you should not use that skill until Rey will be targetable.