How to access:
Clear all of the Event stages (except the Co-Op LV 70 stage, which is optional). This will give you access to the CHAOS stage.
Stage Difficulty: Level 180 (CHAOS)
Mission Requirements:
Score 730k | Clear without any KOs | Clear within 90 turns | Take 15000 or less HP damage
Featured Characters: Keiss, Zidane, Cloud, Alphinaud
Many team ideas with and without boosted characters are available in this event’s Call to Arms!
Fight Overview & Team building
A short fight that is incredibly easy if you pulled on this very hyped banner, but if you chose to skip it, had no luck in your pulls, or just want to better understand the mechanics to tackle the TCC Challenge, read on!
Recommended:
- Launchers. They are the main counter to the boss gimmicks this time. Most of the other recommendations here are much less necessary if you bring a good launch-focused team and/or the boosted characters.
- High damage/free turns. This fight has demanding turn count and score requirements.
- A tank, HP damage mitigator or units with Last Stand to survive the killer Sylvan Union combo.
- A turn delayer. Regular breaks won’t delay them during the combo, but skills still can.
- Paralyze/Silence to stop the bosses from executing their Sylvan Union combo if you can’t cancel it via launches.
- Debuff evasion or cleansing to deal with their dangerous
MAX HP Down, SPD Down and 
Sap
Avoid:
- Evasion-focused tanks, like Prompto or Edge, because the bosses’ worst move has a guaranteed hit.
- Characters with Water-based attacks, because the first wave absorbs this element.
Summon options:
- Any, choose based on what your team composition needs.
- If you bring Leviathan, do not summon in the first wave since they absorb water.
Wave 1: Cray Claw x2
| BRV Attack |    attack |
| Wallop |  attack |
| Tail Drill | attack; increases BRV; inflicts MAX HP Down; grants  DEF Up to self“+” version: greater BRV increase |
| Slime |  attack; inflicts SPD Down, Sap |
| Shake Off |  attack |
| Scissor Grab | attack; inflicts ATK Down |
Tail raised high…!: Raises ATK, DEF, SPD, INT BRV, MAX BRV (activates at 80% HP)
Tail raised higher…!: Raises ATK, DEF, SPD, INT BRV, MAX BRV further (activates at 50% HP)
Enrage: No. They do not power up when the first one dies.
The first wave is very short, since these foes have nowhere near the same HP as the actual bosses, but it serves as a good training for what comes later. They are fast and can cause delay with their skills or decrease your team’s SPD with debuffs, so watch out for turn order. Their main feature is being able to get a high amount of BRV quickly from their attacks and Sap, while giving you little time to react before unleashing it as HP damage. Using a tank or delayer, as outlined in the Team Building section, greatly reduces their threat.
Their other annoying feature is inflicting MAX HP Down, which makes your characters very vulnerable to instant KOs if you don’t keep the enemies broken. Sadly, it cannot be thrown back by Yuffie this time, since they are immune (the same applies to the next wave as well).
Wave 2: Biosoul x2
| BRV Attack | attack |
| Wallop | attack |
| Ivy Screw | attack; increases BRV; inflicts MAX HP Down “+” version: delays target 1 turn |
| Slime | attack; inflicts SPD Down, Sap “+” version: delays target 1 turn |
| Shake Off | attack |
| Garden Grab | attack; inflicts ATK Down “+” version: delays target 1 turn |
| Sylvan Union | attack; moves own turn to just after ally; reduces by 75% the BRV damage taken by that Biosoul; party turns cannot be delayed by Break (lasts until it uses an HP attack in its next turn, or if one of them is Launched; effects end with “Union Severed!”) |
| Life Powder | Grants target BRV |
| Venomous Liquid | Recovers from Break; attack + attack; guaranteed hit |
Tail raised high…!: Raises ATK, DEF, INT BRV, MAX BRV (activates at 80% HP)
Tail raised higher…!: Raises ATK, DEF, INT BRV, MAX BRV further (activates at 50% HP)
Moving nimbly…!: Raises ATK, DEF, SPD, INT BRV, MAX BRV further (activates when one dies)
Enrage: Yes, see above.
The Biosouls have a very similar modus operandi to their smaller cousins, using most of the same moves and debuffs. The big difference is their special three-part combo:
- Sylvan Union, a single-target melee attack that places Biosoul‘s next turn right after the other one’s. It also activates two other effects: It cuts by 75% the BRV damage taken by that Biosoul, and makes both immune to having their turn order delayed by Breaks (but skills can still delay them);
- Life Powder, where the second Biosoul gives a large amount of BRV to the one who used Sylvan Union;
- Wallop (if >80% HP) or Venomous Liquid, a guaranteed hit BRV+HP attack that will convert the BRV gained from Life Powder into big damage to a party member.
Breaking them does not end the combo or remove the protective aura; it will only end by either launching one of the Biosouls into the air, or letting them execute the Wallop/Venomous Liquid attack. The effects have no visible marker, but you will know it ended when the message “Union severed” appears briefly at the top of the screen.
This combo is not as telegraphed as the lizards from the previous Chaos, but it has a clear warning: you need to pay attention to when the message “Craving energy…!” appears after one of their attacks. That Biosoul who just attacked will use Sylvan Union and start the combo on its next turn. At this point, you have a chance to make sure you break or delay them so that the “craving” Biosoul acts after the other one. If his next turn comes immediately before his ally, you will have no chance to react to their 3 consecutive actions.
The Biosouls only start using Venomous Liquid after hitting 80% HP or less, so if you keep one of them close to full health while focusing damage on the other, you can have an easier time whenever it’s their turn doing the HP attack; it will be the weaker version. (tip from Xcaliblur!) Also, the “Craving” foe will never use any move other than Sylvan Union, not even if they have enough BRV to one-shot a party member.
Tools to deal with the Sylvan Union combo:
Launches: if you launch either of the Biosouls after Sylvan Union, the BRV reduction effect ends and they can be delayed by Breaks again. It will not stop the Life Powder skill from happening, but the “craving” Biosoul will not use the HP attack.
Suggested units: Keiss, Cloud, Fujin, Cecil (Dark Knight), Layle
Tanking/HP damage mitigation/Last Stand: As long as you can survive the last part of the combo, you can completely ignore it and deal damage to them as usual. Tanks (except those who rely on Evasion without Last Stand) can survive it with certainty as long as you keep them healed.
Suggested units: Galuf, Snow, Zack, Freya, Porom
HP damage disable/negation/Paralysis: you can deny them the chance to do the follow-up HP attack in the combo – while making them skip a turn won’t necessarily end the aura’s effects, it does give you more time to react and neuter their damage.
Suggested units: Arciela, Beatrix, Cloud, Gilgamesh
Delay: breaking their turns apart is a great way to give you more time to interrupt the combo, and their immunity is only to delays due to being broken, not from skill effects.
Suggested units: Keiss, Lightning, Leo, Vayne, Aranea, Y’shtola