I know if I was in your shoes I probably won't play this game again. I'm already at battle rank 79 and I'm hoping its not too late to get my stats up there to take out absolute conqueror. My best union right now is Rush's union that has Blocter and 3 other soldiers with 4,400 hps. Their damage ranges from 10k to 30k depending on the skills I can select. Omnistrike does close to 30k now. That is my best union though. My weakest is Emmy's union with 3 other soldiers and they only have 2300 hps. At least her Hundred Flowers does about 30k damage. Although that unit regular hits for 8k to 15k.
I'm the kind of person that would like to get all the achievements from my games but I just don't have the time anymore. There are lots of games I want to play (Eternal Sonata and Tales of Vesperia) and if I just don't get the full 1k for this game on this playthrough I'm just going to stop and go on and play the next game on my list. Perhaps if I ever get a downtime between game I'll go back to get achievements but I usually use those times to play downloadable games. I just really liked this game so I'm trying to make an effort to get the 1k for this game. As opposed to Infinite Undiscovery which I did not like at all.