Colosseum is a harder version of Arena. There are 2 rounds, offense and defense, Your units duke it out on both rounds. On Offense, you attack first. On Defense, your opponent attacks first.
The main difference that Colosseum has over Arena is that your opponent units' extra skills, enhancements, and spheres are active. This makes battle more difficult since you also have 0 control over your units just like Arena. So, squad composition and sphere combinations will be more important in Colosseum. The importance varies based on the class you are tackling.
Colosseum has 4 classes and they are as following:
Warrior - Units of Cost 45 and below
Gladiator - Units of Cost 50 and below
Conqueror - Units of Cost 54 and below
Hero - Unlimited Cost
The main difference between these classes is the unit cost restrictions. Warrior is mainly catered to free omni units. This include the starters, Logi, some 7 stars, and Mifune. Gladiator class and above allows many of the current units in the main summon pool.
Hero has no restriction but this leads to a very crazy noticeable difficulty spike. Since any units are allowed, there is a lot you can do to mess with your opponents.
We are going to discuss more about particularly Hero class Colosseum because it is commonly asked. New players may see the word "Unlimited" and think that this is the mode to do since it has no restriction on units. However, the current meta in Colosseum requires certain units that may not be available to you and spheres that one may not have at such an early stage in the game.
As of recent developments, a very common strategy for Colosseum is forming a squad that has 100% mitigation and 100% Battle Crystal (BC) Reduction or BB Reduction. This is done to outlast your opponents. How do we get a 100% Mitigation setup while also maintaining 0BC?
This is an example squad you can use for reference
Neon Winder Rhyne - Ragnarok Edict (RE) + Mark of Spire (MoS)
Lunar Maiden QiuTong - Ortus + Sakura Blossom Medal (SBM)
Lunar Maiden QiuTong - Miracle of Khons (MoK) + Prosklystios
Lunar Maiden QiuTong - Tarok's Bloodlust (TB) + Uln'gha
As to why this squad and sphere combination work, let's do some calculations.
Rhyne - 120% BC Reduction (LS + ES from the QiuTongs + RE + MoS), 20% Damage Reduction (ES from the QiuTongs)
QiuTong - 115% BC Reduction (LS + Ortus + ES from the QiuTongs + Enhancements) + 35% Damage Reduction (MoS + SBM)
QiuTong - 110% BC Reduction (LS + MoK + ES from the QiuTongs + Enhancements) + 35% Damage Reduction (MoS + Prosklystios)
QiuTong - 110% BC Reduction (LS + TB + ES from the QiuTongs + Enhancements) + 35% Damage Reduction (MoS + Uln'gha)
We still need a total of 50% passive damage reduction to pair with our 50% active from QiuTong's mitigation buff.
To do this, we will need to use elgifs and the Omni+3 bonus for Guardian typing for all of the QiuTongs. There are 3 elgifs that give 10% damage reduction passively.
Curse of the Night
After these elgifs are fused and each Qiutong is made into Omni+3 Guardian types, then our QiuTongs will have 50% passively.
Rhyne is in an odd spot considering she won't be at 100% mitigation at all times. However, Ragnarok's Edict has a 100% chance of 20% Damage Reduction and 70% damage reduction after buffs. If Rhyne has a 5% damage reduction elgif, then she will have 75%. This is not truly 100% damage reduction but she will be tanky enough.
Rhyne is mainly here to do her Chance to Negate KO Resistance to hopefully take out key units from the enemy.
Our last slot will be our DoT unit. Since DoT is not affected by mitigation, it will be helpful if you have a unit that can inflict DoT to whittle down your opponents that are running similar setups. For this example squad, we will be using Tate and Tama
Tate and Tama will be equipped with Orphira + Arcane Bulwark and she will be given one of the 5% damage reduction elgifs
Tate will have these passives: 85% BC Reduction, 50% passive Damage Reduction
For Tate, 100% damage reduction is more important. If you want to have 90% BB Reduction, you can make either Rhyne or Tate be a Lord with Omni+3 to get another 5% reduction.
If the example squad mentioned above is not quite within your reach, you can try to do a setup similar to this upcoming example. This squad is used by one of my officers from Elgaia Federation.
Cayena (Lead): Khons + Quintan relic, Brave Regalia elgif
Tate & Tama: Thrilling Harmony + Sakura Blossom Medal, Brave jubilation elgif
Qiutong: Orphira + Prosklystios, Memory of Orebus elgif
Qiutong: Grand Cloak + Uln’gha, 5% miti elgif
Qiutong: Thrilling Harmony + Eremon Aegis, 5% miti elgif
So for beginners and returning players, I recommend doing classes that are not Hero, for the time being. In order to do well enough to not get stressed out and still get the rewards in a timely fashion.
Now, what are the rewards for doing Colosseum?
Colosseum allows you to earn CBP or Colosseum Battle Points. CBP are gained either by losing or winning your Colo battles. You can increase your point gain by using certain units as Leads like the Battle Maidens, that have a boost to CBP gain in their LS, and having a win streak in Colo. You can also increase the point multiplier by using more than 1 Colosseum ticket, which is earned from doing Arena. A list of leads is provided under this information box.
After you have a good amount of CBP, you go to the reward section and from there you use your points to trade for various rewards from the chest selected. In order to unlock better rewards, you need to buy everything in the current reward stage and then you go onto the next stage and continue the same process until you hit stage 100 for the final reward, Heaven Binder. A powerful defense based sphere.
Many of the good rewards from Colo are from the higher stages like Omniscient Blaster and Annihilator Blade. These are powerful spheres used in end game and you should work towards these.
The tip for Colo is that you do whatever class you can win more often in than not. This will help maintain your steady CBP gain. There is also nothing wrong with just losing, you still get points. Colosseum is mainly a grind.
The best time to do Colo is during the 4x ABP/CBP event which is held every month.
So what units you should looking for for Colosseum?
If you want to do Hero class, I recommend looking for units with these aspects:
BB Gauge Reduction
Damage Reduction (Mitigation Buff, Mitigation Passives)
Damage Over Time
Angel Idol Passives
Chance to Negate KO resistance - When the unit attacks, there is a chance the unit will bypass KO resistance.
These are just some things to look for when you are trying to figure out who to use for Colo.
If you do need to move down from Hero into the lower classes, then that is fine. However, you may need to do some experimentation to see what works for you. For Conqueror, it is the same strategy for Hero but you may have more options. The last 2 classes may have different metas but there is currently not a lot of information at this time. I will do research to see if there is any notable strategies.
Good Luck Summoners!