So I learned a pretty good way to grind/farm/get final upgrade items all at once. Probably best to beat the game before doing this. And I'm sure someone has some other way, I'm not saying this is the best.
Requirements:
1.) Death spell for Vanille (she is the only person that can learn it)
2.) Having Archylte Steppe - Northern Highplain and Archylte - Central Expanse teleports unlocked.
3.) Being decently leveled in crystarium, could probably handle with jobs at lvl 4.
4.) Growth egg and the two item catalogs (basically TH for ff13, also these are optional but recommended)
5.) Belladonna Wand / Morbol Wand for higher chance of death (also optional)
Basically you will alternate between grinding on the king behe / huge dog fighting and killing adamantoise with the teleports. You can find the king behe/dog in Archylte Steppe, you will run by them just doing the main story, while your running towards cocoon in the sky, headed to Taeijin's Tower. These two are literally 20 feet away from the Northern highplain teleport. So just teleporting there you will see them.
Basically for this fight I use com/com/syn. When you engage these two, you will always 100% of the time get a preemptive strike, no matter how you approach them. And on top of that they both start at half hp. Your syn will haste the pt then other buffs (when I first started here I played sazh myself so I could choose what buffs took priority). One com will attack the behe and the other will attack the dog, keeping both stagger meters high, so they are very easy to take down. When you first start here the behe will most likely stand up and take a bit longer, but still easy because once the dog is dead you can stagger him. It took me about 35-40 seconds to kill the two when I first came here, after a good amount of grinding I can kill the two in 7 seconds. They give 6600 exp, 13200 with growth egg. Once you kill them run down the path by the teleport till their spawn is out of sight on the mini-map, then come back and they will be back. With 10 second kills and growth egg you can make near 1mil an hour here.
And to deal with the Adamantoise, I make my party sab/sab/sab and cancel set with another sab/sab/sab set. Engaged the adamantoise (the huge turtle with horns, not the smaller guys) then immediately summon with Vanille. The summon knocks him on his ass then just start spamming death until it sticks. Helps to have the Belladonna Wand (or 2nd tier Morbol Wand) to land death, but it's not needed. It really feels like having x3 sab in pt increases deaths chance, and also debuffs like imperial and deshell. But I have no way to prove that, so opinion. When your summon goes away the other sabs will go to town with debuffs and the turtle will still be on the ground for a good while. Most the time death will stick before it stands up, sometimes it doesn't, take the death and retry, no biggy. Adamantoise give 40,000 CP and 80,000 CP with growth egg. They also drop plat ingot which sells for 150k, and the material needed for your ultimate weapons.
Now the reason I do these both at the same time is only because of the tp bar, adamantoise are a bitch without the summon to help knock it down, so I don't bother fighting them without it. So I kill one adamantoise, turn around and run to the central teleport, tele to northern, puts me right at my grinding spot. Kill until I had 3 tp bars, teleport back to central, grab choco and run towards cocoon in the sky, will run you right into a adamantoise, kill, run on foot back to tele. Northern tele again, exp for a decent while all the way up to 5 tp bar. And back to adamantoise. The teleports respawn the adamans, where as normally they dont respawn unless you zone.
Summary:
1.) Kill king behe/dog till 3 (or 5) tp bar is full.
2.) Tele to central, choco out to the adamantoise
3.) Run back to the tele and warp over to the grinding spot to refill tp.
4.) Rinse and repeat.
Ton of cp, gil, and ultimate weapon upgrade items.