Lee Sin had his shield with Lux's shield stacking with Janna's shield stacking with Lulu's shield stacking with 1 hp Karma's shield stacking with 5x Locket of the Iron Solari.

If someone calculates this with a AP build on each character I'll give them nothing but the amazing giant health shield result of this.

Sure it would be funny, but this is not the right thread for it :/

The Locket wont stack, so that kills some of your fun.

But I'll run with some of this anyway:

Assuming all five champions have 700 AP and Karma has her max AP from her passive, plus the unique active, it adds up to 4314. Unless I'm doing something horribly wrong.

Save for that Intervention lasts for 3 seconds and the total shield time is 5 seconds and that stats effect damage to the shield.