This is an outline on how cannons affect gameplay.
We all have discovered how randomly cannons seem to affect our fights. Here are some details about offensive cannons. Defensive Cannons work in the same way, but apply to the defensive stats instead of the offensive stats. When a skill activates a cannon, that card gains a bonus % to it's stat. +1 cannon is 10%, +2 cannons is 15%, and +3 cannons is 20%. Note that using three +1 cannon skills yields three 10% bonuses, not one 20% bonus.
While there are cards that add cannons to all ally cards, the most effective way is to use many of the same nation's cards to pile on the bonuses to every card you can. For instance, in the fights portrayed on this page, I had 2 Nettles, 2 Ebonys and a pixie. I chose this team to have a lot of Bellator cards so that the Nettles could activate their cannons on every card, save the pixie.
The benefits of stacking like this yields stronger attacks for all the cards. Those cards' attack values sum up at about 34k, yet with cannons activating and a few jacob's ladders and other combos, plus the type advantage, the final attack number was over 64k. This was due to the coverfire, two +2 cannon skills applied to cards, and skills and combos. Thus, the nettles and ebonys were much stronger. If I had different cards other than the ebonys, say sanctus cards, then only the nettles would have gotten the cannons, as their skill only applies to bellator cards.
- Note than cannon stacking requires high combo level cards to work efficiently.