Alanaan/Strategy

Strengths

• Can reliably reach the 50% DEF DownDEF is lowered
  Strength: 50% cap alone using  Sun-Touched ParadiseBathe the battlefield in the blazing heat of the sun.
  (Deploy the Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
  Strength: 20% ATK Up / 25% DEF DownMultiplier: PerpetuityDuration: 8 turnsField effect
  Local status effect field effect.) and  Wrath of the Goddess1000% Fire damage to all foes (Damage cap: ~1,080,000).
  Inflict Immaculate SunlightHP is lowered on every turn (Can't be removed)
  Strength: 5% of max HP (Damage cap: 500,000)Base Accuracy: 200%Duration: IndefiniteLocal status effect, 25% ATK DownATK is lowered
  Strength: 25%Base Accuracy: 200%Duration: 4 turnsLocal status effect, 25% DEF DownDEF is lowered
  Strength: 25%Base Accuracy: 200%Duration: 4 turnsLocal status effect, and PetrifiedStops enemy's charge diamonds from filling.
  Base Accuracy: 150%Duration: 4 turnsLocal status effect on all foes.
  Inflict Immaculate SunlightHP is lowered on every turn (Can't be removed)
  Strength: 5% of max HP (Damage cap: 800)Duration: Indefinite on all allies..
  • Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
    Field effect
    Local status effect can function as 25% DEF DownDEF is lowered
    Strength: 25% that stacks with anything and will never miss due to its nature as a local field effect.
•  Renatian CreedAll allies gain 100% TA UpTriple attack rate is boosted
  Strength: 100%Duration: 4 turns and 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 30%Duration: 4 turnsStacking: A.
  Inflict ShortedCharge bar is frozen
  Duration: 4 turns on all allies.
  (Consumes 100% of all allies' charge bar.) provides high burst potential because of fire's love for 100% TA UpTriple attack rate is boosted
  Strength: 100% and 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 30%.
• Can provide a zero-maintenance and permanent DrainDamage dealt is partially absorbed to HP
  and 50% DEF UpDEF is boosted
  Strength: 50% for the party.
  • Can be used to counteract the negative effects of Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
    Field effect
    Local status effect.
  • Evens out the damage per turn of Immaculate SunlightHP is lowered on every turn (Can't be removed)
    which might not be always desirable.
• Immaculate SunlightHP is lowered on every turn (Can't be removed)
  Local status effect is one of the strongest Turn-based DMG debuffs and is also permanent.
• Has a relatively high accuracy PetrifiedStops enemy's charge diamonds from filling.
  Local status effect that is useful to avoid certain charge attacks.
• Enables your party to deal critical hits regardless of element.
• Gradually enables enmity for the party using Immaculate SunlightHP is lowered on every turn (Can't be removed)
  .
• Has two ways to improve the healing capabilities of the party.
• Can theoretically remove debuffs from the party every turn when in the back line.
  • Removes one debuff per turn when a character receives Turn-based DMG.

Weaknesses

• Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
  Field effect
  Local status effect also allows any foe to deal critical hits against you.
  • It also reduces your team's defense and increases the foe's attack, potentially making survival hard.

Bursting

Bursting would be Alanaan's main characteristic with his ability to immensely boost the party's damage output with all 3 of his skills.

• Increasing the damage dealt using the debuffs and buffs from  Sun-Touched ParadiseBathe the battlefield in the blazing heat of the sun.
  (Deploy the Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
  Strength: 20% ATK Up / 25% DEF DownMultiplier: PerpetuityDuration: 8 turnsField effect
  Local status effect field effect.) and  Wrath of the Goddess1000% Fire damage to all foes (Damage cap: ~1,080,000).
  Inflict Immaculate SunlightHP is lowered on every turn (Can't be removed)
  Strength: 5% of max HP (Damage cap: 500,000)Base Accuracy: 200%Duration: IndefiniteLocal status effect, 25% ATK DownATK is lowered
  Strength: 25%Base Accuracy: 200%Duration: 4 turnsLocal status effect, 25% DEF DownDEF is lowered
  Strength: 25%Base Accuracy: 200%Duration: 4 turnsLocal status effect, and PetrifiedStops enemy's charge diamonds from filling.
  Base Accuracy: 150%Duration: 4 turnsLocal status effect on all foes.
  Inflict Immaculate SunlightHP is lowered on every turn (Can't be removed)
  Strength: 5% of max HP (Damage cap: 800)Duration: Indefinite on all allies.
•  Renatian CreedAll allies gain 100% TA UpTriple attack rate is boosted
  Strength: 100%Duration: 4 turns and 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 30%Duration: 4 turnsStacking: A.
  Inflict ShortedCharge bar is frozen
  Duration: 4 turns on all allies.
  (Consumes 100% of all allies' charge bar.) to guarantee triple attacks and further boosting damage by 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 30%
• If ShortedCharge bar is frozen
  is removed, you would have a Full Chain Burst to top it off.

This is especially powerful for fire where you have easy access to both The Sun and Shiva

Survival

Alanaan also offers various means for survival, ranging from damage reduction to HP recovery.

• By activating  The Hierophant UprightWhen Switching to Main Ally: Fire allies gain Blessed RadianceDEF is boosted / Damage dealt by one-foe attacks is partially absorbed to HP (Can't be removed)
  Strength: 50% DEF Up / 25% of DMG dealt (Healing cap: 800)Duration: Indefinite.
  (Can't be reactivated.), the team would get a permanent 50% DEF Up Buff and a 800 HP drain.
  • The DEF Up portion is roughly equivalent to a 30% DMG CutTaking 30% less DMG
    Damage Cut reducing damage taken for all elements.
    Warning! Does not work for Plain Damage!.
•  Sun-Touched ParadiseBathe the battlefield in the blazing heat of the sun.
  (Deploy the Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
  Strength: 20% ATK Up / 25% DEF DownMultiplier: PerpetuityDuration: 8 turnsField effect
  Local status effect field effect.) gives the party a 25% Boost to healing, which also affects the drain of Blessed RadianceDEF is boosted / Damage dealt by one-foe attacks is partially absorbed to HP (Can't be removed)
  and other healing skills.
  • While it may seem counter-intuitive, Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
    Field effect
    Local status effect helps in survival IF used with Blessed RadianceDEF is boosted / Damage dealt by one-foe attacks is partially absorbed to HP (Can't be removed)
    since even with the DEF down from Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
    Field effect
    Local status effect, you would still have a net DEF Up of 25%. Even factoring in the 20% ATK increase towards the enemies it will still be less damage than normal.
• He can also apply PetrifiedStops enemy's charge diamonds from filling.
  Local status effect and 25% ATK DownATK is lowered
  Strength: 25%Local status effect in order to reduce the damage taken by the party.

Backline-Support

While this would also fit under Survival, it is worth noting that his  The Sun ReversedWhen Sub Ally: 20% boost to Fire allies' healing specsHealing and healing cap.
Remove 1 debuff from a Fire ally when that ally takes turn-based damage. provides means of survival even from the backline. And when he does come out to the front line, he will provide Blessed RadianceDEF is boosted / Damage dealt by one-foe attacks is partially absorbed to HP (Can't be removed)
as stated in the Survival section.

Bursting

One of Alanaan's key points is  Renatian CreedAll allies gain 100% TA UpTriple attack rate is boosted
Strength: 100%Duration: 4 turns and 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
Strength: 30%Duration: 4 turnsStacking: A.
Inflict ShortedCharge bar is frozen
Duration: 4 turns on all allies.
(Consumes 100% of all allies' charge bar.) which allows the party to deal massive burst damage in a short amount of time. As such, classes, characters, and summons that can take advantage of it synergize well with him.
Some of the more notable ones would be:
Bonus Fire DamageWill not include characters that do not stack with Alanaan and Other Means to Increase Damage

• Runeslayer →  Dragon BreakConsume all Magic CirclesFire CircleA magic circle possessing the power of fire (Max: 2 / Can't be removed)
  
  Water CircleA magic circle possessing the power of water (Max: 2 / Can't be removed)
  
  Earth CircleA magic circle possessing the power of earth (Max: 2 / Can't be removed)
  
  Wind CircleA magic circle possessing the power of wind (Max: 2 / Can't be removed)
  
  Light CircleA magic circle possessing the power of light (Max: 2 / Can't be removed)
  
  Dark CircleA magic circle possessing the power of dark (Max: 2 / Can't be removed)
  to grant all allies 10% x (Magic CirclesFire CircleA magic circle possessing the power of fire (Max: 2 / Can't be removed)
  
  Water CircleA magic circle possessing the power of water (Max: 2 / Can't be removed)
  
  Earth CircleA magic circle possessing the power of earth (Max: 2 / Can't be removed)
  
  Wind CircleA magic circle possessing the power of wind (Max: 2 / Can't be removed)
  
  Light CircleA magic circle possessing the power of light (Max: 2 / Can't be removed)
  
  Dark CircleA magic circle possessing the power of dark (Max: 2 / Can't be removed)
  ) Bonus DMGDeals bonus DMG for one-foe one-ally attacks
  Strength: 10% x (Magic CirclesFire CircleA magic circle possessing the power of fire (Max: 2 / Can't be removed)
  
  Water CircleA magic circle possessing the power of water (Max: 2 / Can't be removed)
  
  Earth CircleA magic circle possessing the power of earth (Max: 2 / Can't be removed)
  
  Wind CircleA magic circle possessing the power of wind (Max: 2 / Can't be removed)
  
  Light CircleA magic circle possessing the power of light (Max: 2 / Can't be removed)
  
  Dark CircleA magic circle possessing the power of dark (Max: 2 / Can't be removed)
  )
  (Max: 80%)Duration: 1 turn . (Max: 80%.) (Cannot be used without Magic CirclesFire CircleA magic circle possessing the power of fire (Max: 2 / Can't be removed)
  
  Water CircleA magic circle possessing the power of water (Max: 2 / Can't be removed)
  
  Earth CircleA magic circle possessing the power of earth (Max: 2 / Can't be removed)
  
  Wind CircleA magic circle possessing the power of wind (Max: 2 / Can't be removed)
  
  Light CircleA magic circle possessing the power of light (Max: 2 / Can't be removed)
  
  Dark CircleA magic circle possessing the power of dark (Max: 2 / Can't be removed)
  .)
• Warlock →  ChaserAll allies gain 20% Bonus DMGDeals bonus DMG for one-foe one-ally attacks
  Strength: 20%Duration: 3 turns.
• Tien → 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 30% and Salted WoundATK is boosted when foe is in break mode
  
• Fraux → 20% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 20%Self and Nightmare ScarletDMG taken is boosted
  Local status effect
• Shiva → Guidance of the BlazeATK and DMG cap are boosted / DMG taken is reduced (Can't be removed)
  and Dance of Nataraja
• Anila → 40% Extra Superior Element DMGDeals bonus superior element DMG for one-foe one-ally attacks
  Strength: 40%Self, StrengthATK is greatly boosted based on how high HP is
  , and Hidden Tiger, Crouching DragonAttacks made with elemental superiority have a chance to deal boosted DMG / Double attack rate is boosted / ATK is boosted / Debuff resistance is boosted / Charge bar is boosted
  
• Metera (Fire) → 80% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 80%Self
• Beatrix (Summer) → Nayde VanaroosaATK is boosted against foes in overdrive / Cut to overdrive gauge is boosted
  Self
• Shiva (Summon) → Path of DestructionATK is boosted
  
• The Sun → Double StrikeAttacks twice each turn
  and Sub Aura.

Special Mentions

• Luchador →  Tag TeamAll allies attack without using up a turn. in order to artificially add another turn to the duration of  Renatian CreedAll allies gain 100% TA UpTriple attack rate is boosted
  Strength: 100%Duration: 4 turns and 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 30%Duration: 4 turnsStacking: A.
  Inflict ShortedCharge bar is frozen
  Duration: 4 turns on all allies.
  (Consumes 100% of all allies' charge bar.).
• Mechanic → Allows immediate activation of  Renatian CreedAll allies gain 100% TA UpTriple attack rate is boosted
  Strength: 100%Duration: 4 turns and 30% Bonus Fire DMGDeals bonus fire DMG for one-foe one-ally attacks
  Strength: 30%Duration: 4 turnsStacking: A.
  Inflict ShortedCharge bar is frozen
  Duration: 4 turns on all allies.
  (Consumes 100% of all allies' charge bar.) without Strike Time.

Survival

Another key point is his ability to greatly improve the survival of the party via his Support Skills. Blessed RadianceDEF is boosted / Damage dealt by one-foe attacks is partially absorbed to HP (Can't be removed)
allows fragile characters to survive longer while both  Benevolent Soul25% boost to Fire allies' healing specsHealing and healing cap when the field effect Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
Field effect
Local status effect is active. and  The Sun ReversedWhen Sub Ally: 20% boost to Fire allies' healing specsHealing and healing cap.
Remove 1 debuff from a Fire ally when that ally takes turn-based damage. increase the healing capacity of the party (including Blessed RadianceDEF is boosted / Damage dealt by one-foe attacks is partially absorbed to HP (Can't be removed)
).
Some of the more notable ones would be:
Healing

• MC Classes: Sage, Runeslayer, Doctor
• Characters: Flesselles, YuelAs a note, Yuel's Bonus Fire DMG does not stack with Alanaan's, Io (Summer), Anthuria, Athena, Zahlhamelina
• Summons: Lucifer, Athena

Fragile Characters

• Beatrix (Summer)
• Zahlhamelina
• Beatrix (Halloween)

Weapons

Alanaan can either greatly reduce the damage taken by the party in order to maintain Stamina, but he can also help in letting the party take more damage to dip into Enmity with the use of Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
Field effect
Local status effect and Immaculate SunlightHP is lowered on every turn (Can't be removed)
. These make him versatile enough to be able to function well with both stamina and enmity setups of fire. The weapons for such setups are Ixaba, Crimson Finger, Ecke Sachs, and Ancient Ecke Sachs.
Sun-Touched ParadiseCan deal critical hits regardless of element / ATK is boosted / DEF is lowered
Field effect
Local status effect also allows the party to deal critical hits regardless of element, this especially improves the usability of Ancient Ecke Sachs, Ecke Sachs, and Benedia outside wind and null element fights.
Outside of damage boosts, Fire of Prometheus and Zhuque Lyrewings deserve special mention to their ability to trigger the debuff removal of Alanaan's  The Sun ReversedWhen Sub Ally: 20% boost to Fire allies' healing specsHealing and healing cap.
Remove 1 debuff from a Fire ally when that ally takes turn-based damage. every turn.