Arena/Archive

Setup
Various special rules could be in effect. If your unit has a forbidden ability, you'll still be able to use the unit, but that ability will be blocked. The Party setup screen shows you which units have abilities that are forbidden. Select an opponent and battle begins. Opponents may have a ratio between 0.50 and 1.50.

Opponent list will reset every 10 minutes. Between minute 0 to 4, the list might switch back and forth between old and new list. Once it hits minute 4 (e.g. :04, :14, :24,...), the list will change to the new one for the remainder of the 10 minutes.

Special Rules
Every week, the arena will have special rules that consist of 2 forbidden and 1 bonus. Forbidden rule forbids you to use abilities of the specified type, while bonus gives 30% stats bonus, including HP and MP, to unit of the specified game series. Stats bonus stacks with everything else as it uses unique buffs. Special rules will change every week, predetermined by the developer, usually to coincide with a new event or unit.

List of possible bans:
 * Black magic
 * White magic
 * Physical attack combos: Multi-action abilities like Barrage. Dual Wield is not affected.
 * Magic attack combos: Dualcast, Dual Black Magic or Presence of Mind.
 * Recovery abilities
 * Elemental attacks: Light, dark, etc.
 * Status ailments
 * Parameter boosts
 * Parameter reductions

Battle
Each battle consists of 10 turns. At the start of each turn, there is a roll for initiative. Players will fight until either one team is KO'd or the 10 turns expire. If time expires, decision is based on how many units are KO'd during battle.

Ranking Points
After the battle, you gain ranking points. You gain 10 points for losing. For winning, you will gain points equal to your opponent's ratio times 100, increased by your streak bonus, rounded to the nearest whole.

Medals
The number of medals you earn per battle is simply the number of rank points gained divided by 12.5, rounded to the nearest whole. This also applies to losses, which yield 1 medal each.

Streak Bonus
Your streak bonus is based on the number of consecutive wins you have achieved (including the current battle) as shown in the table below: Note: The screen, after you select your opponent but before the battle begins, displays bonus of the previous win; in other words, your bonus may actually be 1% higher than is shown just before the battle (or 10% higher for the battle after the first win of the streak).

Daily rewards
Receive daily rewards by participating 5 times a day. Losing also counts, and there are no separate rewards.

Weekly competition rewards
The type of stats pot given as rewards are rotated every week starting on Friday, 00:00 PST. Rewards are usually mailed two days after the weekly arena period ends.

Monthly competition rewards
The type of stats pot given as rewards are rotated every month. Rewards are usually mailed several days after the monthly period ends.

Medal Exchange Panel
After each Arena battle, you obtain Arena Medals which can be exchanged for rewards. The Arena Medal exchange system is a hexagonal grid, like the ones used to train Espers.

Completing an exchange board requires 1020 Arena Medals, upon which one will receive a pot. To see which pot you will get after completing the current board, tap on the chest in the middle of the board. There are 7 boards which are cycled in the order shown the following table (left to right):

It takes a minimum of 510 Colosseum/Arena orbs to complete all 7 boards (~73 per board), though 600-800 would be more realistic when factoring losses and the unavailability of 1.50 ratio opponents during the first day of each week. For comparison, it takes a minimum of 825 orbs to complete all rounds of the Colosseum plus 88 more to craft the Blood Sword.

Enemy AI

 * The team you fight against will not necessarily attack how you expect them to, the AI can be very easy.
 * Provoke and similar abilities do not work for their targeting priority.
 * Can use any available abilities including those from equipped Equipment, Esper, and materia.
 * Will always use Limit Bursts whenever one becomes available.
 * Will use self-damaging abilities (e.g. Darkness) without caring about their own survival.
 * Will typically only use curative abilities if at least 1 character's health is in the yellow.
 * The same applies for the removal of Status Ailments although AoEs (e.g. Return) can be used in the absence of any ailments.
 * Will reapply buffs/debuffs that are already up.
 * Will never use:
 * Curative abilities offensively (against your Cloud of Darkness).
 * Any revival abilities.
 * Guard.
 * Esper evocation.
 * Non-effect abilities (e.g. Analyze, Escape).
 * Jump or Hide abilities.
 * Item-related abilities (e.g. Drink, Throw).
 * Stealing abilities (e.g. Pilfer, Mug).
 * Hexes

Every time you enter an arena battle, the enemy will select an AI pattern seen below. This pattern is used as a priority order, sequentially starting from the top. This pattern will persist throughout the whole battle, and not randomized per turn.

Offensive (27% chance)
1. 100% chance to use a limit burst

2. 40% chance to use an offensive ability (requirement: turn 1/3: none, turn 4/6: <70% HP, turn 7/10: <50% HP)

3. Recovery:
 * 100% chance to clear status ailment if status applied
 * 100% chance to heal if <30% HP
 * 50% chance to heal if <50% HP
 * 30% chance to heal if <70% HP

4. 30% chance to use a support ability

5. 100% chance to use a normal attack

Recovery (27% chance)
1. 100% chance to use a limit burst

2. Recovery:
 * 100% chance to clear status ailment if status applied
 * 100% chance to heal if <30% HP
 * 50% chance to heal if <50% HP
 * 30% chance to heal if <70% HP

3. 30% chance to use a support ability

4. 40% chance to use an offensive ability (requirement: turn 1/3: none, turn 4/6: <70% HP, turn 7/10: <50% HP)

5. 100% chance to use a normal attack

Auxiliary (26% chance)
1. 100% chance to use a limit burst

2. 30% chance to use a support ability

3. Recovery:
 * 100% chance to clear status ailment if status applied
 * 100% chance to heal if <30% HP
 * 50% chance to heal if <50% HP
 * 30% chance to heal if <70% HP

4. 40% chance to use an offensive ability (requirement: turn 1/3: none, turn 4/6: <70% HP, turn 7/10: <50% HP)

5. 100% chance to use a normal attack

Aggressive (20% chance)
1. 100% chance to use a limit burst

2. Offensive:
 * 100% chance to use an offensive ability on turn 1/3
 * 30% chance to use an offensive ability on turn 2/5
 * 90% chance to use an offensive ability on turn 6
 * 30% chance to use an offensive ability on turn 7/10

3. Recovery:
 * 100% chance to clear status ailment if status applied
 * 100% chance to heal if <30% HP
 * 50% chance to heal if <50% HP
 * 30% chance to heal if <70% HP

4. 30% chance to use a support ability

5. 100% chance to use a normal attack

General Tips

 * To make your arena party static, you can go to Menu > Option and select arena party. The chosen party will always be your default arena party.
 * Damage is normally limited to 999 per attack but can hit higher due to Chain Attacks (+0.1x max per Chain Attack, or +99 Damage if you hit 999 normally), making strong single-hit abilities weaker. Healing an enemy Cloud of Darkness can also go over this cap or you can use Raise/Full Life to instantly kill her.
 * Barrage can deal up to 4*999 dmg (8*999 for Dual Wield units). Other abilities noted by a  as its attack hits (Default Unit Attack) will also go over the cap, with an odd example being Lasswell's Exorcising Storm, which is an AoE attack that hits twice and if dual wielded hits 4 times, which can equal (2 or 4 w/ Dual Wield)*999 AoE dmg.
 * AoE magic and elemental chains are recommended, as these will go higher than the 999 cap and stack in damage fast.
 * Any ability that gives killer bonuses against Humans (ie Man-Eater and Transcender) are extra strong, as most units are classified as a Human.
 * Tank units are generally not useful unless they have strong cover abilities and healing such as Cecil.
 * Osmose and Lance can remove a great deal (if not all) of an enemy's MP, severely limiting their options to normal attacks and passives like Cover.
 * Death is a forbidden ability but can be used if gotten via Recall (24%) or Slot (25%).
 * Using petrify-inflicting weapons and abilities in arena secures easy wins, since petrified units are considered defeated. The status effect can be removed by Stona, and other status removal abilities, but the AI will rarely, if ever use them. Using a weapon that inflicts petrify such as Golem's Staff, Basilisk Steel, or Razzmatazz with Multi-hit abilities such as Barrage or Bladeblitz synergizes well as it has a chance of inflicting petrify to every unit hit. Using an ability that inflicts petrify adds to the chance as well.
 * Equipping status resistant items such as Ribbon, Discernment, or Moogle Crown can be used to defend against opponents that inflict status ailments.
 * In the event of being affected by status ailments, Ling's Dance of Life, Terra's Ray of Hope, or other similar abilities are effective at removing several status ailments from the caster or from all allies. It is advisable to protect your status remover from statuses by equipping them for immunity if they do not have innate immunity.
 * Stop is a status effect that can be nullified by abilities such as Resist Stop. When a unit is stopped, they cannot take any action nor evade any attacks for 3 turns. Some notable abilities for inflicting stop are Noctis's Blizzard Flask, Amelia's Ricochet, and Chizuru's Dismissal. It is highly recommended to take out these units first.

Status Ailments

 * Inflicting status ailments can make your fights significantly easier. Noteworthy abilities are:
 * Boo!
 * Aura Ball
 * Hex Strike
 * Dance of Death
 * Cursed Card
 * Toxic Rain
 * Fire Flask
 * Chaos Grenade
 * Also consider status-inflicting weapons combined with hit-all attacks:
 * Mage Masher
 * Rune Staff
 * Venomous Edge
 * Golem's Staff
 * Thorned Mace
 * Empress Birch
 * Siren's Alluring Air and Lullaby can be useful on enemies who don't have resistance and are easily accessible.
 * As for elemental attacks: try to guess the esper your opponent has equipped to his units:
 * Golem on tanks
 * Ifrit and Titan on physical DPS
 * Shiva and Ramuh on mages
 * Dispelga and Bushido - Freedom can be very useful for removing buffs from the opponent party.

Handling Physical Evasion Units

 * Mug has a 100% chance to hit, but it will only hit once even with Dual Wield.
 * All skills that draining enemy MP will do so even if they miss, making it easy to incapacitate units.
 * Skills that inflict Stop or Paralyze will cause subsequent hits (excluding hits in cascade of Dual Wield) to never miss. A held target cannot dodge.
 * Black magic. If it's banned, skills such as Exdeath's Wicked Light and Earth Shaker are still usable.
 * So long as the opponent does not have death resistance, Odin or any Death dealing skill can be used against them.
 * Using Doublehand-type abilities or most 2-handed weapons will heighten a unit's accuracy allowing it an increased chance to hit their opponents regardless of how much evasion they have.