Unlocks at the end of the Zerberiya: Sword and Wings Mythos: Song of Sword and Wings of Lost Paradise, chapter 4
Chasselas Crystal Region - Subsector 
Skills: Unseen (Hidden Boss)
|Start of each turn||Randomly pick an element from Earth, Fire, Shade, Thunder, Water, or Wind. If an elemental zone is active, picks that element instead. |
Gains Counterattack: Deals 9999999 damage to attacker when hit with an attack of that element (2 turns)
|-||Distortion Barrier||Self Type RES Up L + Physical RES Up L (1 turn)|
|-||Invisible Slash||Crystal-type slashing attack on all enemies|
|-||Penetrating Malice||Crystal-type piercing attack on 2 random enemies|
|-||Psychic Smash||Fixed 2000 damage on all enemies + Inflict Confusion|
|-||Sudden Crush||Crystal-type Priority blunt attack on a single enemy + Inflict Stun|
|AF Stopper at 30% HP. (31.9M / 13.7M)
Afterwards, uses 2 attacks per turn for the rest of the battle.
Yields 1000 Prism Dust on defeat.
- This boss deals so much damage, and has such an unpredictable attack pattern, that it's hard to set up a sustainable defensive rotation. Your best bet is to field a mixture of your strongest DPS and strongest buffers, burst it down to its HP stopper from turn 1, and then with a collection of buffs initiated during or shortly after the AF, deplete the rest of its HP in one go.
- Melissa and Thillelille are fantastic units for this fight. Melissa's Flash Strike stance greatly contributes to a fruitful first turn AF, while Thillelille's raw damage can carry the fight to its conclusion.
- Similarly, since the boss is weak to Crystal, units that can inflict Crystal element damage are good choices for damage dealers. Eva and Nagi (Extra Style) can both hit for a lot of Crystal damage. Also, the boss will never use its counterattack against Crystal attacks.
- Rage doesn't affect which targets Penetrating Malice will hit.
- Counterattacks used by your party won't trigger the boss's counterattack, so you can use moves like Philo AS's Store Power freely without worrying about which element the boss will counter.
- It is possible to set up enough mitigation to make the boss's damage manageable by applying enough type resistance, physical resistance, and/or PWR down debuffs, and if you also have a way to nullify or cleanse Confusion, you can last a long time fighting defensively instead of maximizing your damage and trying to win the fight in two turns. However, there are a few other things that can make this strategy hard to pull off successfully.
- Because the boss can hit very hard on the first turn, you might end up losing a character before you get all your mitigation set up. You can deal with this by using a turn 1 AF just to set up your defensive buffs, being fast enough with your mitigation and lucky enough to have everyone survive whatever attacks the boss uses at the beginning of the fight, simply replacing anyone who dies with a back row character, or using Mariel AS to resurrect them.
- Psychic Smash does fixed damage that can't be mitigated, and once the boss is at 30% or less of it's max HP, it uses two attacks per round instead of one, which means that there's a chance your entire party will take 4000 damage in a single turn. Most characters won't survive this unless you've boosted their Max HP. The simplest way to avoid dying to this is to activate Another Force right after the boss hits the HP stopper and finish it off immediately, but you can also try boosting everyone's max HP above 4000 or using Sophia's party-wide Hold Ground buff.
- Some characters that help when fighting defensively:
- As always, the Chrono Cross characters are always useful both offensively and defensively.
- Mariel is good in both her NS (with Manifest Weapon) or AS forms. Both forms can heal, apply a 50% Type resistance buff, and cleanse status ailments. Her NS form has a decent typeless Magic attack and a stronger heal, and her AS form heals both the front and back row and can resurrect dead characters.
- Sophia has a physical resistance buff and a stacking Type Resistance buff on the same skill. She can also give a Hold Ground buff to the entire party.
- Many characters have a very useful 30% PWR debuff, but Soira (Another Style), Azami with her True Manifest, and Radias (Another Style) can stack PWR debuffs up to 60%, and Mistrare (Another Style), Orleya, and Kid can debuff PWR up to 50%.
- You can use upgraded HP Restore grastas to pass your defensive buffs to your damage dealers to bring them up and use them for AF. This is, of course, best done immediately after entering the second phase.
- You can also establish a Magic Zone to help reduce damage, as Unseen lacks a magic attack. One Magic Zone setter, Rosetta (Another Style), is also capable of providing some heal utility.
In order to battle Unseen, you must destroy the 3 cat statues in the area containing the portal to Unseen's location. https://img.altema.jp/anaden/shasura.jpg