FINAL FANTASY XIII-2

I managed to get this achievement on my first kill of the boss and I was not at all power leveled. my highest level was maybe 70 in com / rav and the others in their 30s and 40s.

To start the fight you want to have Rav x2 and 1 Com. My party was Chichu as the com. You need to take down Garnet Bahamuts HP to near death but DONT kill him. switch over to Amber Bahamut at this time and take him out then once hes dead, garnet should die seconds after. ( I did this because I assumed they were on a fixed timer for their re-spawn )

Then once both are out of the way I used Sab /Sab / Com ( again Chichu as the monster ) this way I was able to apply poison asap.. I wont say its a must have but it will destroy Jet Bahamut 10 times faster with poison on him. and it should garentee a 5 Star rating.

In just using that strategy I killed Jet Bahamut before any of the 2 others re-spawned and killed him more than half the time needed.

Note: I want to also point out that my Chichu is not leveled up to its Max level of 70.. he was at level 30 or so when I did this boss fight.

The way I unlocked the achievement was to get both characters' roles to the 90s. From there, I set up the following Paradigms:


Com/Com/Com (Bethemoth)
Rav/Rav/Rav (any of the Ariman-type monsters)
Med/Med/Med (Flanitor)
Sen/Sen/Med (Flanitor)
Sab/Sab/Rav
Syn/Syn/Med (Flanitor)

The way I do battl is attack the Amber Bahamut first with the three Ravs and once it stagger, shift to the three Coms until it is dead. From there, I switched to the Sab/Sab/Rav paradigm and get both Deprotect and Deshell on the Garnet Bahamut, then switch to the three Ravs to stagger and to the three Coms to kill it.

For the center Bahamut, I went with the Sab/Sab/Rav combo to get Deprotect and Deshell on, then back to three Ravs to stagger it and then to the three Coms to damage and used the Bethemoth's Feral Link ability to attack it and give my characters some much needed buffs.

If all goes according to plan, you should kill the center Bahamut before he revives the other two Bahamuts and get the five stars for the achievement.

I just beat the final boss of the game with a 5-star rating, first time. It was actually quite easy if you know what to do.

Firstly, you want to make sure your monsters are leveled up, it makes battle A LOT easier. I had a level 36 Flanitor to heal, a level 20 Dragoon as my commando and a level 24 Pleuston as my ravager.

You also want to make sure Noel and Serah are leveled up well, making sure Serah is a level 99 ravager and Noel is a level 99 Commando. For equipment, i used iron bangles and a magicians mark for Serah. Noel had a power wristband, a silver bangle and a grimoire hat. I recommend playing as Noel and using potions to heal if necessary as the hat increases the amount of health you will heal.

Now for the Paradigms, these are the ones i used:
Rav, Rav, Com Relentless Assault
Rav, Com, Med Diversity
Med, Com, Med Discretion
Sab, Syn, Med Evened Odds
Rav, Rav, Rav Tri-disaster
Com, Com, Com Cerberus
You will probably want a paradigm with sentinels though as the boss can do some strong attacks.

When you get into the battle use Relentless Assault against the two weak monsters and kill them as you would usually kill a monster, they aren't hard at all. Now when jet comes out you will want to use Evened Odds to buff your party and de-buff him, don't spend a long time doing this though as you will waste time. After that, stagger him and keep using ravagers until his stagger bar is around 600%, you then want to use a triple commando class to damage him.

He will summon the two weaker forms again so just repeat the process but if you don't kill jet on this second turn, restart the battle as your won't get a 5-star rating. Heal when you need to and use Noel to heal with potions. I won the battle in around 8 minutes with a target time of 11 minutes. You can also play on the easy difficulty if you want.