

But those are not the only type of banners, there will buff banners give more damage, more def, magic def etc. For an example say you're pve'n and you are low on def and the monster is gonna hit you with a massive blow. Call down a def banner or a magic def banner to increase you're overall def and absorb the blow.
You can have 6 banners in you're load out but only 3 can be out at once. Example would be mixing a fire debuff/dot like flame curse with a fire attack banner and a magic amplifier banner, for huge magic damage. Doing this gives you huge burst but the trade off would be maybe you take 3% more damage and if you miss it opens you up for a counter attack.
Along with banners you can do a melee attack, or a ranged attack with a ranged weapon. Yes i didn't forget about the fight between banners, since banners will have a cooldown after their timer is up. The banner system is not limited by just magic attacks, there will be buff banners for those who want to play the tank/assassin/bowman/cannonier
Let's not forget the trusty healer and support banners. I already explained one debuff banner at the top, but there is more potential for debuffs such ass attack slowing/cast time slowing debuffs lowering certain def attributes and like a said there is buff banners buffing melee/magic damage Healing banners will be have basic healing, healing all party members, Siphoning life from target and putting it into either the banner user or a party member (think leech seed from pokemon but instead it lasts until banner timer is up)
I think this system would work best and RPG, but there is possibilty to go for action also if made it a load out based team fight game. I've only thought of the idea as a rpg type so far. I can probably expand more on this if i think about the system more like maybe making the banner level with the character or make 6 cast banners with a mix of 5 passive banners in a skill tree type way. I don't really know yet i'll think about it and go more in depth about it maybe Monday. Thanks for reading.
TL;DR Use banners to do debuffing buffing magic and heals with different mixes and combinations