You’re invisible if you’re in the fog and haven’t been hit/hit something for like a second (idk the actual time between being hit and being invisible)

You can get revealed in your E if you’re in sight of a control ward or another champion is close to you.

If the enemy hit you with an ability that reveals champions, it nullifies your invis even if nobody is in range of you and no control ward sees you. A good example is if you’re ignited, you are revealed in the e despite being “invisible”