Brave Frontier

none except michele and that isn't max crit. I need a nuker. I can get by with the friend avant using bb

That's unfortunate. Gaiza misses out on so much spark damage that he's not really a nuker anymore though. You can easily out damage him with a 500% BB mod units that spark well, especially if they have higher attack stats. Guys like Toutetsu, Rhoa, Mahalu, and Ciara are all solid options if you have one. Mifune's still super viable too, provided you give him Four Bonds to keep his HP up.