Stadium

The Stadium is located in Heyama City accessible late in the story after the events at Fort Shaul. It houses some of the best rewards in the game. Any battle costs 100G and if you lose you are simply returned to the front desk with full HP.

Singles Rank
Single battles must be fought with only one character at a time. If you keep losing with one character, experiment with different characters, equipment, and Shards. Reward: Blob Jelly Reward: 100G Reward: Thick Pelt Reward: Refined Shellac Reward: Devices Crafting Book - Modifiers Reward: Moon Feather Reward: Prism Water Reward: Fruit of Endurance Reward: Ex-Hearten Reward: Refined Corollas Reward: 1000G Reward: Scope (device) Reward: Fruit of Life Reward: Salve Reward: Apple Loaf Reward: Tropical Salad Reward: Prism Serum Reward: Fruit of Power Reward: Inferno Bell Reward: Quints Reward: Crystal Prism Reward: Refined Rime Reward: Toni Notes: Equipping Pulse Torc is necessary since it always goes first and inflicts with all kinds of negative status ailments, which effectively prevents you from being able to hit it at all. Reward: Fruit of Resistance Notes: Powered up and now only ranged attacks hit Reward - Attack Spike Notes: On the first turn one of them uses Enkindle which makes them all explode. You'll probably die unless you have the Inferno Bell equipped or have very high HP. Reward: Prism Tonic Notes: Absorbs 40 TP from you and then does a move that damages based on your current TP. Make sure you are near fully charged before he uses this. Reward: Spectrum Notes: Need high evade to dodge his initial strikes. Eidol is great here and her Rapid Strike deals massive damage due to the Angst's low AGI. Reward: PP Double Reward: Penrose Notes: Loses MDEF with each hit. Sandra's Gatling works well or even Enda's Tatsumaki if MP isn't a problem. Reward: Celestial Signet (used to charge Neutron Star X at Central Shoal) Notes: Needs to be hit by each element once. Each element hit deals around 5000 damage and then locks it so that element won't hurt it again. You can't just spam all elements though, they need to have some power behind them otherwise he'll be left with a good amount of HP and no way to damage him. Bring lots of summons for each element and charge up your TP a bit before using each. Also when his "eyes glow red with flames" you need to use Flare Shield (Slash Shard) to block a strong fire attack. When his "eyes become encased in ice" you need to use Frost Shield (Asera Shard).
 * 1) Blob
 * 1) Rensa Grub
 * 1) Barotian
 * 1) Shield Bug (Dark)
 * 1) Cobble
 * 1) Static Fly x4
 * 1) Chimera
 * 1) Sludge
 * 1) Deformity x3
 * 1) Gorger
 * 1) Shield Bug (Wind) x2
 * 1) Scorched Ice x2
 * 1) Birch
 * 1) Shield Bug (Earth) x3
 * 1) Blood Widow x4
 * 1) Koro x3
 * 1) Refuge
 * 1) Quills x2
 * 1) Phantasm
 * 1) Gremwhile
 * 1) Floe (power 70)
 * 1) Graupel x8
 * 1) Relic
 * 1) Cosmic Glowbug x2
 * 1) Sentry Orb x4
 * 1) Stadium Ghoul
 * 1) Sewer Angst
 * 1) Wind Wraith
 * 1) Gridlock
 * 1) Arc

Team Rank
Team battles are fights where you can use 4 party members at once, just like normal battles. Reward: 250G, no need any strategy Reward: Shibuichi Helm Reward: HP Spike I found this is challenging since King Gorger will attack twice in the start of battle and causes a lot, I mean A LOT, of status ailments like DELAY and BLIND and then he will summon its pawns (max 3 pawns), use any magic/technique that has Area of Effect, kill the King first. Reward: Glacial Bell Reward: Fruit of Spirits Reward: Torrent Bell Reward: Sun Feather Reward: Fruit of Intellect Blob? NAH. Just use your strongest magic to kill 4 monsters and then use physical attack to beat another 2... why? you will know Reward: Penrose Deals 6,000 AOE damage on turn 1 and every 4 turns after that (1, 5, 9, 13, 17) and starts mixing up a 3,000 AOE damage later on. Much later in battle (turn 21) starts using 9,000 AOE damage. Use armor with plenty of slots and load up on maxed HP Spikes. Kill him before turn 21. Reward: ??? (Vertex Shell)
 * 1) Weaklings
 * 1) Drudgor
 * 1) King Gorger
 * 1) Scourge
 * 1) Terra and Storm
 * 1) Chaw
 * 1) Flash Golem
 * 1) Tough Guys
 * 1) Grim
 * 1) ??? (Attrition)

Challenges
Challenge battles are unique fights with a very specific set of rules. Each battle is different and may take some experimentation. Make sure to read each fight's hint message. Hint: Win five battles in a row Strategy: Simply win five easy fights in a row. Reward: Fruit of Energy Hint: Each hit angers this beast. Strategy: Each hit makes the boss stronger. Try to only use high damage single hit strikes like Macrocosm or Fire 4. Reward: Silver Bracer Hint: Win with half a team. Strategy: Use only two party members. Reward: Eternal Lantern Hint: Goes easy on injured groups. Strategy: Your starting HP determines this boss's power. Weaken yourself significantly in the Theatre District dungeon next to the Stadium and then start the challenge. The boss will be exceptionally weak. Reward: Fruit of Chance Hint: Win five battles in a row. Strategy: Simply win five fights in a row. Reward: Gale Bell Hint: Stop trying to hit me and hit me! Strategy: Use moves like Sandra's Bulls-eye which never miss. Reward: Prism Serum Hint: Blocks all but the strongest of hits. Strategy: Blocks all hits that aren't critical and only takes 1 damage per hit. Eidol's Weak Point skill has an 80% crit rate. It has 16 HP so you need 16 critical hits. Reward: Gold Bracer Hint: Damaged only by Shards of the deepest red. Strategy: Load up characters with summon Shards and have Throg feed them TP. Use characters with plenty of slots. Reward: Onyx Pin Hint: Win five battles in a row. Strategy: Win five difficult fights in a row. Reward: Arctite Helm Hint: Defend against Fire, Ice, and Dark attacks. Strategy: This boss uses AOE fire, ice, and dark attacks that will most likely kill your party. Equip three characters with the Inferno Bell, Glacial Bell, and Shade Bell and also give each of them a method to revive other party members. This boss will take a long time to recover after using one of the big magic attacks so use that time to revive everyone and get in a couple hits. Reward: Halo Ring Hint: Defeat in one move or face the consequences. Strategy: It says one hit but it's really one move. Load up Xero with as much attack as possible, the Glass Cortex armor, and maxed Attack Spike Shards. Charge up his TP Link and unleash hell. You don't need to worry about taking damage while charging up. Reward: Penrose Hint: ??? Strategy: Uses several moves which apply status effects to one member in your party. These moves are named "Grime" and set a variable to match the last status effect used. He then uses a move named Cleanse every 5 turns which kills party members which are NOT under that previous status. For example if he uses Sticky Grime then one character will be Delayed. He will then kill everyone who is not Delayed on turn 5. The strategy is to try and put negative status effects on yourself before he cleanses and then cure them after. Reward: Osmium Helm
 * 1) Onslaught I
 * 1) Pain Gain
 * 1) Shorthanded
 * 1) First Impression
 * 1) Onslaught II
 * 1) Stay On Target
 * 1) Critical Reception
 * 1) Summoning Courage
 * 1) Onslaught III
 * 1) The Bell Tolls
 * 1) One and Done
 * 1) ??? (The Cleansing)

Rays
You can choose any Ray that you have captured and battle its monster. You do not lose the Ray when doing this.