Ok.. I've completed the side quest for the monster arena in the calm plains.. just one problem.. what do i need to open the treasure chest?

This is what u need to open the treasure chest this is what u have to do:

The owner will ask you to capture fiends from all over Spira, You'' get prizes when u return to the owners with the required creatures. Some of the monster are very rare so it will take time, but anyways, you get rewarded for each time you accomplish one of the following:

Capture one of every fiend in every area

or

Capture 10 of every fiend of a specific species

or

Capture 10 of every fiend in every area

Complete a total of 10 of either species conquest or area conquest for the mars sigil, which will unlock the chest in the calm lands. (The one at the monster arena of course)

Hope i helped somewhat ^^

__________________

I think he means the treasure chest with Yuna's Nirvana lol.

You need an item called the Celestial Mirror. Refer to www.ffextreme.com in the FFX Section I believe there's a guide.
Hope I helped as well.
-Kujamune

__________________
[glow=darkblue]Cross My Heart, Hope Not To Die, Swallow Evil, Ride The Sky. Lose Myself In a Crowded Room, You fool you fool it\'ll be here soon..[/glow]

Thank you Lulu.. I was wondering what I really needed to do.. I already had all the monsters from Calm Lands ( dont know where i came up with calm plains... ) anyhow thanx again for the help

Well I don´t know if you really want to know but if you capture all fiends 10 times and defeat all original monsters the trainer creates you can fight nemesis one of the strongest bosses in the game (I believe you can steal level4 key spheres from him if you need any).

__________________

quote:
\"Final Fantasy without humour is like an easter egg without a ribbon.\"

No problem, glad i can help, and u get aurons weapon out of that chest also. collecting the monsters isnt that hard, i did it in 5 hrs lol. I think u can do it too.

__________________

All I have to say is good luck.....I got sick of searching for the damn monsters when it took me 2 hours just to find 5 Simurghs on Mushroom Rock Road.

__________________

To open that chest, and to get all of the Celestial Weapons, you need the Celestial Mirror which you can get by getting the Cloudy Mirror by winning the chocobo race near Remiem Temple (not the one against the trainer).
You can refer here for more detailed info.

__________________
Eikre: \"Galgarion is Cherry\'s butt?! This is gonna be the coolest boss fight ever!\"
Ronald: \"You\'re talking to a guy who forgot he was fixing a toaster and instead built a time machine.\"

LOL
YA U NEED DA CELESTIAL MIRROR
THEN ULL B SWEET
ITS PRETTY SIMPLE

__________________
[glow=blue]Summoning is our...[/glow]

[glow=blue]...Last Hope[/glow]