JP Boss Guide by /u/Zurai001

Multiplayer Enemy AI by /u/TFMurphy

BOSS: Yunalesca (X)

Difficulties: 160 (Ultimate ) and 220 (Apocalypse )

Mastery Conditions:

• Win with 4 or more party members alive.
• Reduce Yunalesca's ATK.
• Reduce Yunalesca's DEF.

Overview:

• Yunalesca is weak to Water, and absorbs Holy.
• Her 3 phases are at 100% (default), 80% (weak) and 50% (very weak) respectively.
• In her default phase, she uses a standard PHY attack, and Absorb, which does heavy NAT physical damage to one target and heals Yunalesca. While in this phase, she also counters all attacks with Counter Sleep/Blind/Silence.
• Once her HP has been taken down to below 80%, she will enter Weak phase, and starts off with Hellbiter on everyone - this does a small amount of NAT physical damage to all party members, and Saps them.
• In this phase, she has access to Ultimate: Holy (hits three random targets that are Sapped with heavy Holy-elemental physical damage), and Osmose (removes a charge of a random ability for all party members). She also has access to Ultimate: Mega Death (KO's one random party member) in this phase. She loses the Counter Sleep/Blind/Silence from this phase on, but she also gains a Counter Attack that removes Shell/Protect/Haste.
• When she is brought down to 50% HP, she will enter Very Weak phase, and opens once again with Hellbiter.
• During this phase, she retains all her attacks from last phase, and gains two new attacks - Mega Death (KO's one random party member - no idea what the difference is between last phase's one. Apparently she loses Ultimate: Mega Death and gains Mega Death), and Mind Blast (AoE NAT non-elemental magic attack that has a chance to apply Confuse).

Tips:

• This fight was infamously bugged when it came out in JP - will it be the same for Global? The bug is that Mega Death is supposed to ignore characters that are Sapped, but in the actual game, it would still kill them anyway. Let's wait and see, but I don't expect it to to be a fixed version.
• If Mega Death is not fixed, I highly recommend your party to have some form of AoE Regen (Kirin, Memento of Healing). Since there is literally no benefit to remaining Sapped, except to eat back-to-back Ultimate: Holy (which really hurts, in combination with the damage plus her near instant actions).
• Mega Death is not totally unavoidable however - it can be blocked by Physical and Magical Blinks. Do note however that Last Stand does not prevent Mega Death.
• Some good units to use include:
  • Firion - His BSB ensures high uptime on Magic Blink. Especially so if he was dived for Support 4 for Wrath access.
  • Arc, Penelo - Arc's SSB2 and Penelo's USB are instant cast heals that come with Physical Blink (in the case of Penelo's it also comes with HP Stock).
  • Tyro - BSB and Wrath spam gives you Magic Blink, and Protectga/Shellga.
  • Yuna - This fight was literally made for her USB. Bunch of dead bodies everywhere, activate USB, and everyone's good to go.
  • Bring your best Water users otherwise. Tidus' CSB was made for this fight too.