Star Ocean: The Last Hope

There are extremely cheap ways to beat Tamiel. I used Edge and Meracle, primarily (best stick some symbol users and healers for the other two spots).

Edge and Meracle had maxed out Critical Hit and Chain Combo skills and were around level 45. After Edge's rush gauge was full, I let him have it with an Edge/Meracle rush combo, which left him with a sliver of life. From there, it was a simple matter of finishing him off. It took around two minutes.

If you're not able to kill him this fast, you must watch out for his laser attack when he gets low on health, especially when he goes into rush mode.

Also, Tamiel is easy to juggle, so you can smack him around with Edge and Meracle until he enters rush mode, switch to someone like Reimi to preserve your bonus board, and switch back and commence the juggling when Tamiel's rush gauge is gone.

This achievement is earned by beating the 4th boss on the 4th planet of the game. Sadly, this is not an easy task, even if you are a high level (unless you aren't playing on galaxy diff.)

The best method to beat the boss is to use Reimi or Faize in this battle, their really short-to-charge and long range attacks will help to stay away from the boss, as his attacks are very powefl and can do from 800 - 1400 damage in 5 to 7 hits.