A 3★ Ifrit Multiplayer AI Battle from the Japanese server using only Attackers.
A 1★ Tyro Multiplayer AI Battle from the English server with 2 Attackers and 2 Breakers.
For both vids, please check the video description for more information.
Depending on the bosses, I do actually use AI Defenders and Supporters too. ^^ For most of the 1 and 2-star ones on Mobius FF JP, I only need Attackers. Things start to get tricky once I move onto 3-star because it really depends on whether or not I have the ability cards or not.
For example, other than Vanille & Fang, I have no strong single target Water mage cards. 
And the only AOE one I have is a 5-star card with Blizzaja which consumes 6 orbs. That’s a death sentence for my Attackers had I opted to use that in the Ifrit battle. .___.
I’ve yet to try my non-mage water attacker jobs, but high magic power is needed for quickly finishing battles so I don’t think I have much choice.
As for 4-star AI, I haven’t attempted it yet. In fact, I haven’t done any 4-star battles even with live players since I keep thinking I’ll be a burden to everyone. I’m just afraid of misreading their attacks which will ultimately screw things up. >_>
Examples: As a Breaker, I really need to pay attention to how many people are using abilities because if other players make the Break bar go red, then it’s completely unnecessary for me to use abilities. But sometimes, I’ll throw one or two in because I didn’t keep their actions in mind. -___-;
Similarly, if they’re attacking and sending the boss into Break then I really shouldn’t be just physically attacking the boss. 😛 The only good thing that comes out of that is generating orbs.
Edit: *___*! I finished my first 4-star battle! It was with an AI party too! No one died! 😀
I know the clear time is nothing special since I wasn’t aiming to do a speed run or anything. I just wanted to survive and complete the battles. :3
koukoupuffs 