Otherworld Colosseum

A set of five No Continues stages in two difficulty levels, under Special Stages in the Legend Stages menu. Every Otherworld Colosseum map runs one battle rule that changes how the fight works — tap the icon at the bottom-left of the stage select to see which rule is in effect, and expect some Cat Combos not to activate under it. Unlocked by clearing A New Legend (Uncanny Legends). The event is one of the few sources of Dark Catseyes.

Each run is five Rounds (200 energy each, No Continues, bases of 1.2–2 million HP) with its own enemy rosters; the wiki keeps a page set per run. We host the two newest runs' rounds — enemy rosters, magnifications and spawn order — as stage pages:

• Colosseum: Rarity Draft (Rarity Draft: Duo) — Rounds 1–5 →
• Colosseum: Half-Off Plus (Half-Off+: Special) — Rounds 1–5 →

Rewards are not collected automatically — tap Claim on each mission once its condition is met.

One rule per map, cycling between runs. Names and descriptions are the in-game text; the detail line is the wiki's explanation.

1. Trust Fundおこづかい制
   Start the battle with a ton of Money, but gain no Money over time or by defeating enemies.
   The player starts with 50,000¢ and cannot gain money from defeating enemies or by the Worker Cat. All units will start on their cooldown, and any money-related Cat Combos are prohibited.
2. Cooldown Equality生産スピード統一
   Deploy cooldowns will be fixed at the same rate for all friendly units.
   All units have their cooldown set to 16.67 seconds. Research Combos are prohibited.
3. Only One Rarityレア度代表戦
   Only one unit from each Rarity can be deployed at once. Your Cat Army can be set up as you please.
   Only one unit from each Rarity can be deployed at once. This only affects the battle, not creating the lineup.
4. Cheap Laborワンコイン
   All allied units can be deployed for 500￠.
   All Cat Units have their cost set to 500¢.
5. Super Rare Sale特売セール　激レア
   Super Rare units can be deployed at half-cost with half the cooldown speed.
   The cooldown time and deployment cost of Super Rare Cats has been set to 50% of their original time / cost.
6. Deploy Limit生産キャラ数制限
   A maximum of 60 units can be deployed.
   The amount of units that can be deployed throughout the battle is limited to 60. The Iron Wall Cannon and Conjured spirits do not count towards the limit.
7. Special Clearance超特売セール　EX
   Units of Special rarity can be deployed at 30% cost with 30% cooldown speed.
   The cooldown time and deployment cost of Special Cats has been set to 30% of their original time / cost.
8. Plus One: Uberプラスワン 超激レア
   Uber Rare units are automatically deployed two at a time.
   Deploying an Uber Rare Cat will summon another one 2 seconds after deploying the first one. Uber Rare Cats with Conjure will also be deployed twice and conjuring their spirit will summon a spirit for each of them.
9. Mega Cat Cannonにゃんこ砲超強化
   Cat Cannon Power is now SUPERPOWERED! ※ Does not affect attack power of Special Cannon effects like Thunderbolt.
   The Cat Cannon will deal $1x more damage. This only affects the Default Cat Cannon and not the other Cannon Types.
10. Uniform Motion等速直線運動
    All ally and enemy units move at the same speed.
    All cats and enemies with at least 1 speed will have their speed set to $1 speed.
11. Plus One: Specialプラスワン EX
    Special units are automatically deployed two at a time.
    Deploying a Special Cat will summon another one 2 seconds after deploying the first one. Special Cats with Conjure will also be deployed twice and conjuring their spirit will summon a spirit for each of them.
12. Uber Clearance限定超特売 超激レア
    The number of Uber Rare units deployable is limited, but their cost and recovery time are reduced.
    The cooldown time and deployment cost of Uber Rare Cats has been set to 50% of their original time and 5% of their original cost, but only $1 {{plural|$1|Uber Rare Cat|Uber Rare Cats}} can be deployed at a time.
13. Limited Stock現品限り
    Only 50 Units total can be deployed over the course of this battle, but all Units have the same recovery time.
    All units have their cooldown set to 16.67 seconds, and a maximum of 50 non-Conjured/Iron Wall units can be deployed. Research Combos are prohibited.
14. Dirt Cheap二束三文
    All allied units can be deployed for 10￠.
    All Cat Units have their cost set to 10¢.
15. Pay Day給料日
    Start with a huge amount of Money, but earn none over time or after defeating enemies. Uber Rare unit Cooldown reduced to 20%
    The player starts with 266,730¢ and cannot gain money from defeating enemies or by the Worker Cat. All units will start on their cooldown, and any money-related Cat Combos are prohibited. The cooldown time of Uber Rare Cats has been set to 20% of their original time.
16. Grand Battle大勝負
    Uber Rares cost double, but are deployed three-at-a-time.
    Ubers have double the cost and recharge time, but in return deploying one will spawn 3 of them, with a 60f delay between each spawn.
17. High Speedハイスピード
    All allied and enemy units' movement speed is increased. Allied units' deployment cost and recovery time is decreased.
    All units have their cost and recharge time set to 70%. All units with at least 1 speed will have their speed doubled.
18. Half-Off: S. Rare半額セット 激レア
    Deploy cost of Super Rare Units is halved, with two units deployed at once.
    Super rare cats have cost set to 50% and spawning one will spawn another 60f later.
19. Inflation: Uber Rare物価高騰 超激レア
    Start with much more money, but gain no income over time or by defeating enemies. Uber Rare deploy cost is also doubled!
    Start with 60k money and don't get any more (like trust fund). Ubers cost twice as much as usual but only have 70% of the cooldown.
20. Half-Off+: Special超半額セット EX
    Special Unit deploy costs are halved, with deploy cooldowns shortened by 30%! Plus, two units will be deployed at once!
    Special cats have cooldown shortened by 30% and spawning one will spawn another instantly.
21. Rarity Draft: Duoレア度選抜+1
    Only one unit of each Rarity can be equipped in your lineup. However, two units will be deployed at once!
    ?

Global: October 1–15, 2024. Japan: July 1–15, 2024 (added in Version 13.5).