Did you know that it is possible to stack certain Main Character Passives? This thread is honestly just a place-holder, until I can properly experiment and come up with an extensive list, but I just want to let people know on 1 combination that I KNOW works, and can be extremely useful.

So many of you know that Gai's life leech ability stacks with the Lightning Main's life leech. Many of you also know that the Water Main's Healing Tips ability stacks with the Healing Tips of other ninja, like Kabuto.
BUT, did you know that the Healing Tips passive of the Water Main also buffs the Life Leech of the Lightning Main?
In addition, the life leech ability will spread to all 12 ninjas on the team, as long as the Lightning Main remains alive. This provides a tremendous advantage in places like Great Ninja War, but especially in Strong Approaching, where the ability to regain your health can mean the difference between success and failure!