Stealth

Stealth is a buff that can temporarily prevent a unit from being targeted by single target attacks; it does not protect a unit from AoE attacks. It can also provide the unit with an ATK%, DEF%, REC%, and/or Critical Hit Rate% buff, which should stack with other procs and passives that also boost those stats.

Trivia
On release, Aegis Cloak had a Stealth effect that made it impossible for units in arena to target it, making enemies skipping their turn as a result. This sphere’s effects were changed later on. Netherking Hadaron was the first unit to have the Stealth effect, and due to how the Stealth mechanic worked at the time, AoE attacks would not be able to target him if he was the only unit alive, forcing enemies to skip their turn. This was heavily exploited by players that made Hadaron solo Trials until the Stealth mechanic was fixed to counter this issue.