Nina

Weapon: Spy-Song Bow (+EFF)

Assist: Positional Assist / Flexible

Special: Noontime / Sol / Moonbow  

Passive A: Atk/Spd Solo / Atk/Res Solo / Close Foil  

Passive B: Null Follow-Up / Lull Atk/Spd / Null C-Disrupt 

Passive C: Atk Smoke / Pulse Smoke / Joint Drive Skills / Flexible

Sacred Seal: Atk/Def Solo / Atk/Spd Solo / Spd/Res Solo / Mirror Stance / Swift Stance 

• Nina’s access to Spy-Song Bow makes her an interesting option for an AR-O unit, with its assortment of effects—in tandem with her specialized statline—working well to help her shine. Her pairing of low HP and Defense may appear to clash with this role, but the flexibility of being ranged does give her the opportunity to safely eliminate melee threats during the initial Player Phase; Blessings, support, and investment will also help. 
• Healing Specials work fantastically here to maximize Nina’s longevity through even further sustain on top of her Spy-Song Bow’s built-in healing. Noontime is great for instant activations on each counterattack, but Sol may be used instead if Brave Lucina support is available. If Spy-Song Bow’s healing is sufficient, Moonbow is an option for a consistent damage boost. 
• Nina can leverage standard stat-boosting A slot skills to great effect due to her range making tanking melee threats potentially unnecessary. Of those available, Atk/Spd Solo provides Nina the most general usefulness through its massive offensive boost, though Atk/Res Solo is an option for magic specialization. At higher investment, Close Foil (or Close Counter) is a potential candidate to maximize her versatility.
• Null Follow-Up is immensely useful to let Nina shut down foes with automatic follow-ups and/or follow-up negation—effects that are both ubiquitous and lethal in Aether Raids Defense teams. Although not quite as strong, Lull skills grant Nina a greater stat advantage over foes (with the most useful being Lull Atk/Spd), and Null C-Disrupt may be considered to handle Dazzling Staff healers. 
• Smoke skills synergize wonderfully with Nina’s defensive playstyle; the AoE debuffs they aid her ability to trade blows with multiple foes at once. Atk Smoke further supplements her pure tanking capacity, but Pulse Smoke is a highly compelling choice to work around Infantry Pulse setups. For her Sacred Seal, anything that enhances her key stats—preferably a Solo or Stance skill—works excellently. 

Weapon: Spy-Song Bow (+EFF)

Assist: Positional Assist / Flexible

Special: Moonbow / Noontime 

Passive A: Mirror Stance / Distant Def / Atk/Res Solo

Passive B: Null C-Disrupt / Mystic Boost / Lull Atk/Spd

Passive C: Atk Smoke / Smoke Skills / Joint Drive Skills / Flexible

Sacred Seal: Spd/Res Solo / Swift Stance / Mirror Stance / Distant Def / Mystic Boost 

• Nina also has the recourse of focusing purely on countering incoming magical threats and adopting a purely defensive playstyle—which also makes it easier to consistently enable the positioning required for her refined Spy-Song Bow. A +SPD IV helps mitigate the amount of damage she takes by denying her opponent’s follow-up attack, but increasing Attack or Resistance are worthwhile considerations as well. 
• Mirror Stance is an excellent A skill choice to fortify both Nina’s damage and magical durability, and even comes packed with built-in Guard in its third-tier version—something greatly useful for fighting mages with automatic doubles. Other options include Distant Def (for better archer matchups and buff negation with its fourth-tier version) and Atk/Res Solo. 
• Since Nina’s Speed is high enough such that she should generally not need Quick Riposte (outside of wanting to break through Impact effects), her B slot is open to other powerful skills such as Null C-Disrupt to counter Dazzling Staff healers, Mystic Boost for more healing and broader anti-magic capabilities, and Lull Atk/Spd for a stat advantage.
• Smoke skills are once again one of the prime recommendations for Nina’s choice of C skill, as they still complement a defensive playstyle perfectly. Joint Drive skills are also always welcome—if available, of course—to enhance Nina’s stats while offering some support to her allies. Otherwise, her C skill is flexible, as is her Sacred Seal which should be occupied by anything that enhances her key stats.

Weapon: Spy-Song Bow (+EFF)

Assist: Positioning Assist / Flexible

Special: Moonbow / Iceberg / Luna

Passive A: Sturdy Impact / Atk/Spd Solo / Swift Sparrow / Fury 

Passive B: Null Follow-Up / Lull Atk/Spd 

Passive C: Wave Skills / Smoke Skills / Flexible

Sacred Seal: Atk/Spd Solo / Swift Sparrow / Death Blow / Atk/Def Solo / Flashing Blade

• The Eye Spy can ditch a defensive-oriented set altogether—especially since Spy-Song Bow’s effects are not restricted to a particular phase—and go for a more aggressive approach instead. Enhancing either of her offensive stats here with an Asset is recommended to elevate her damage potential. 
• Moonbow is a consistent Special choice that should generally activate in each round of combat—provided she performs a follow-up attack—but for stronger damage boosts, Luna and Iceberg can be considered. Specifically for those utilizing the Flashing Blade seal, Glacies can prove particularly potent and scales nicely with Nina’s Resistance. 
• Sturdy Impact is one of Nina’s best A skills for an offensive set to circumvent her otherwise abysmal physical durability, granting +10 Defense and follow-up negation on top of an amble damage boost upon initiation. This is rather high investment, though, so standard offensive A-slots that are more readily available (Atk/Spd Solo, Swift Sparrow, Fury) can work as well. 
• Since Spy-Song Bow’s healing clashes with Desperation’s low HP threshold, it’s generally best to use other B skills instead. Null Follow-Up is excellent to ensure that Nina’s doubles—which she is highly dependent on for her damage—regardless of any follow-up negation her opponent may have. Lulls are also good to break past enemy bonuses, though it’s worth noting that those that detract from her opponent’s Defense may prevent her weapon’s bonus damage from activating. 
• This build’s C-slot is flexible, though Attack or Speed-increasing Wave skills are always solid candidates for increased firepower (or Smoke skills when refresher support is available). Aside from Flashing Blade for faster Special activations, any seal that boosts Nina’s key offensive stats is recommended.