The Lure of Echidna

The Lure of Echidna is a Global-exclusive Trial in Final Fantasy Brave Exvius found in the Chamber of the Fallen. The Trial pits players against Echidna.
==Battle==
The players face Echidna across different levels in advancing difficulty (ADV, PRO, ELT). In ADV she's at 1,250,000 HP and doubles her stats with each level, topping at 5,000,000 in ELT.
Echidna abuses status ailment-inflicting attacks and uses both Physical attacks and Magic, so the player needs to be well prepared. Echidna attacks five times per turn and at first uses normal attacks along with Tornado (Wind Magic + Confusion chance to all units), Toxic Claw (Physical Damage + Poison chance to all units), Death Kiss (Instant KO at 50% chance to single unit) Reap Blood (Hybrid damage + HP Drain and chance to inflict Disease to single unit) and preemptively using Soul Siphon (Hybrid damage + MP Drain + chance of petrify to single unit), and never using any of these more than once per turn each (except her normal attacks). She will also at times use Seduce to inflict Charm on a single unit (Charm is considered akin to Stop: it is not a status ailment so it can be Dispelled).
Echidna is vulnerable to Blind and Silence, but if affected by either of those she will use Ecdysis as her first move to remove them. As she passes the 50% threshold she gains access to Flare (Fire Magic Damage; hers is a different version with a chance of Blind and attacks all units, but does not reduce Water resistance), Tremor (Earth Magic Damage + chance to Paralyze to all units). Flare and Tremor can be prevented by inflicting Silence and Blind respectively, which will force her to use Ecdysis and use Soul Siphon or Toxic Claw instead. 
As her HP reaches lower levels, she will gain an immunity to Silence and Blind, thus making it impossible to nullify her moves.
==Strategy==
Echidna has high HP but low defensive values of 50 DEF and SPR, so the player will be able to do high damage. However, unless the player has a setup with multiple high tier chainers (like Orlandeau, Fryevia) and/or chain finishers (like Olive) that can finish the battle quickly, the player will likely engage on a mostly defensive game with Echidna, while reducing a small percentage of Echidna's HP per turn and enduring the bulk of her cruel attacks.
Given defeating her quickly is a reserved privilege, the player will need to prepare, especially against her status ailments. Confusion can be devastating as it will cost the player turns and may become fatal if a high ATK unit attacks a party-unit causing death. Paralyze and Petrify can also hinder the player significantly. Blind and Poison are annoying but not compromising. To deal with Confusion, the player has two options. One is to equip the whole party with Confusion-nullifiers like Black Chokers (although equipping the whole party will prove costly in terms of Star Quartz). The second option is to equip as many units as possible with anti-Confusion such as attackers or healers and bring Minfilia due to her Leader's Disposition helping protect the party from Confusion for three turns. Healers should be protected against Confusion and Paralyze while the Tank should be immune to Petrify and Death (Safety Bit can be acquired in Sorcerer's Hideaway) as it will take the brunt of the single target attacks, and the two aforementioned ailments are compromising and regularly used.
Minfilia can provide protection against Confusion and reduce both Wind and Earth damage, so she should be left to cycle between all of them (Earth not mandatory until close to 50%), equipping her with Protection of the Gods is also helpful as it can trigger major heals. Two healers are also endorsed. Luka is an excellent choice as her Priestess' Miracle can heal and remove status ailments, and she comes with Deep Blue that will greatly enhance the party's defenses for five turns. The other healer should be either Y'shtola, due to her dualcasting ability (along with occasionally useful Protectga and Shellga), or Refia (provided she has Dualcast) due to her natural resistance to ailments and Full-Raise. Another viable option is Roselia, as she can heal the party's HP and MP making her a good MP battery so as to not use items as per the Missions (however, this will come at the cost of healing capability). Ling is another useful MP battery who can remove status ailments and has her own immunities.
Noctis is an excellent choice to use in this fight due to his versatility. His Cover ability provides useful HP and MP Regen, and if needed he can use Point-Warp to restore most of his HP and MP; however, since it is a Jump attack, he will be unable to act after he attacks. His Fire Flask is fairly useful as it can inflict Echidna with Blind and Silence, forcing her to use Ecdysis, thus reducing her number of attacks from 5 to 4 per turn. This is especially useful later on to prevent Echidna from using Flare or Tremor. Noctis should be equipped with Dual Wield as he may quite well be the only attacker. As a Tank Cecil is useful, but Snow will prove to be significantly better. This is due to his innate Draw Attacks, which coupled with Golem's Provoke, will ensure 100% targetting from Echidna. Snow also has good defensive stats and HP and can counter both Physical and Magical attacks, making him a great contributor for Limit Bursts or the Esper Gauge (killing Echidna with an Esper is a Mission).
In ELT the party's units should have at least 4200+ HP. In case wind resist is missing for any reason after turn 2, Tornado/Venom Claw/poison damage hits for 3900-4100 while having only have 180-200 SPR. So the player should equip Materias to boost HP and defenses (those from King Mog's events are good at doing both). 
In ELT Echidna will begin with with Soul Siphon which will likely target Snow. The MP should be restored instantly so that Snow can use Provoke (if Noctis' Cover is the only source for MP, provided the player wants to achieve all Missions, then the player may have to risk a turn). Minfilia should cycle protections (the player should check their party's units to check which one they need to apply. Whichever is missing, they should apply, with Confusion protection being a priority.) Healers should heal at all times and if there is room for it, buff the party as well. Echidna's Seduce is not a status ailment, so Dispel is the only option. Either normal Dispel or Odin's Fingernsap will do. The player will have to reapply buffs afterwards (including Provoke as the Tank will be the primary target). However, if the tank had cast Provoke immediately before Seduce, then they do not need to do so as Provoke lasts for 3 turns while Seduce lasts 2.
Once Echidna drops to approximately 25%-30% she will be immune to Silence and Blind, so the player will likely face Flare and Tremor. Her strongest attacks in unison (Toxic Claw, Tornado, Flare and Tremor) can kill the party, but if the buffs are up, they should survive (Anti-Fire buffs are not a priority).
As such, the entire battle will mostly be a test of endurance. Healing and cycling between buffs, regenerating HP and MP and attacking whenever possible. If doing all Missions at once proves too difficult then the player should aim to do those they can at a time. Defeating her with a 5-man party and using items OR using a 6-man party but not items are some ideas (in the latter's case two Noctis are a good idea to provide solid coverage of options).
==Trivia==
*Echidna is based on the boss from Final Fantasy III.
*Cloud of Darkness is a good unit to use in this boss fight due to her resistances to elements, status ailments, and her abilities Omni-Veil and Comeback, which increase elemental resistance and heal several status ailments respectively.
Category:Final Fantasy Brave Exvius events