I know there are a lot of methods for Trema but I'm going to post my method.
First of all, equipment.
Yuna should have a cat nip and speed bracer equipped.
Rikku should have the same as Yuna.
Paine should have an adamantite and sprint shoes equipped. This means that Paine has 255 defense and 255 magic defense and can act first in battle. She should be on the garment grid that gives the biggest defense and magic defense boost (if she doesn't have 255 defense and magic defense).
Yuna and Rikku = Gunners
Paine = Dark Knight
First of all, get Paine to use a stamina tonic. Get one of the gunners (who should be in yellow HP after beating Paragon) to use a potion on her whilst the other one uses target MP on Trema. Then get Paine to stand by for healing/draining MP from Trema. The other two should target MP/trigger happy at Trema. Eventually he should die.
I hope this helps. :D
Nope, doesn't help. First, Target MP would take forever since Cat Nip doesn't affect MP ( use Soul Spring or Mana Springs ). Second, you must play 2 games to get 2 Cat Nips. Third, you should first have both Gunners throw a Stamina Tonic at Paine and have Paine use a Megalixir, Elixir or X-Potion because one Gunner ( or both ) will likely die before using a heal item, especially when in low health already, and Paine is slower, so the heal is likely to happen before the Stamina. ( See the 3 Zshare video links on my youtube profile, though I give Trema 3-Stars for Infinite MP to make it more of a fair fight ).
It worked for me.
I know I have two cat nips. I got to the 40th floor twice. On my first playthrough, I didn't attempt to beat Trema.
I know cat nip doesn't affect target mp. That's why I said the dark knight should be there for healing and draining mp.
Finally, my gunners managed to heal my dark knight fine. I do see what you mean, though.
Don't see why people rely on cat nip so much when game can be easy as hell already without it. The only boss I had problems with was Chac.
Anyway, my Trema strategy:
GG: valiant Lustre
DSPS: Dark Knight on all 3
ACC: Paine with Adamantite and Crystal Bangle (will usually max out def and 9k ofHP), Rikku with Crystal Bangle and Crystal Gloves, Yuna also with Crystal Bangle and Crystal Gloves. The other 2 girls had around 160 def and 8k+ of HP IIRC.
LV: no idea what's the lowest, my average middle of all 3 was around 88-90 and that was overly easy, so it's possible on lower levels.
Paine and one fast character throws Mana Spring (or the better one, I didn't have it), 2nd fast throws Light Curtain. Then Paine and one fast repeat Mana Springs, while 2nd fast uses Lunar Curtain. Finally Paine and one fast finishes with Mana Springs, while 2nd fast throws Chocobo Wing. If Trema isn't all out of MP, you can do another round with Mana Springs, and optionally throw Healing Spring. I didn't, but it might make the battle a bit easier.
Now Trema only goes with phydical attacks and you will spam Darkness with all 3 Knights.
When any knight reaches 3k of HP or goes Bellow, heal with the X potion.
EVen with all 3 Knights at 3k of HP Meteor should be able to kill the party, so after it, just throw X potions again.
Now simply keep casting Darkness and heal with X potions when needed, survive another, Meteor, reheal, and Trema should be down in no time.
The cool thing about no MP is that Trema will also give you free rounds in later stages of battle, since he will try to contanstly cast spells such as Demi or Ultima (Ultima only once that is), but he will fail to cast them due to no MP.
This battle with strategy above will last around 10 minutes, and what's better you'll feel better because there were no cheap tricks such as Cat Nip involved.
Oh yeah, typo: meteor SHOULDN'T be able to kill your party with at least 3k+ of HP, my bad. Twitchy fingers :P
The much loved Non Oversoul Chac:
-Songstresses equipped with 2 Rabbite's Feet...
-use Matador's Song to increase Evasion to never be hit by Chac's physical attacks
-use Magical Mask to bypass Heaven's Cataract's damage, use Matador's Song to increase Evasion by 10/12 again in order still not to be hit by Chac's physical attacks even with a greatly reduced Luck Stat due to Heaven's Cataract
-inflict damage via Momentum through the Samurai's Honor garment grid
Migth as well post my Trema setup:
All girls were lvl 99. GG was Valiant Lustre with Dark Knight, Lady Luck(With Item Reels) and Gun Mage(With Annihilator)
Paine on Lady Luck(She's my choice girl for LL) with Sprint Shoes and Adamantite.
Yuna on Dark Knight with Crystal Gloves and Invincible.
Rikku on Dark Knight with 2x Crystal Gloves.
First I CONGRATS!'ed Paragon to quickly get it out of the way. Once the battle with Trema began, I immediately moved all three girls through the gates for the defense boosts. Once Paine was back on Lady Luck, I had her use Item Reels for a Mighty Guard+, while I had the other two girls use a Stamina Tonic and X-potion on Paine. Once Mighty Guard+ was up, I switched all three girls into Gun Mage, used a Three Stars and spammed Annihilator, using White Wind to heal HP and Chocobo Feathers to heal Stop. For the most part it went smoothly, though I suppose a bit of luck comes into play at the beginning.
I also used this setup to get Cry in the Night on all three girls in the same battle.
Justin Beiber brings all the girls to the yard,
and they're like "Can you even get hard?"
Just thinking that next year will be 10 years since this game came out!
Boy does time fly!
It also feels forever since I stopped by ;)
Old habits die hard...
Never Say Never Again!
I'll weigh in then buddy!
Use your 1st run through to get things to make your second run that bit easier.
*AP Eggs from calm land secret cave and blitzball - makes mastering dress-spheres a cakewalk
Also, clear O'aka's debt before chapter 3. Then spend a couple hours buying 99 hi-potions from him @ 50 gil, then sell them to the other shop in the celsius for a tidy profit. if you can do that, you can carry over 900,000 gil to buy the besaid key in chapter 1! this'll get you some neat stuff early on in run-through 2, and help get that 100% a little easier.
Alternatively, you your ill-gotten gains to bribe your way through some nasty bosses in Via Infinito.
Biggest tip of all - enjoy this game. It's nothing compared to FFX, but it pulls FFXIII's pants down in public.