Shinon

Preferred IV: +ATK or +SPD or +RES

Weapon: Double Bow

• Surprisingly, this is the first ranged weapon to have inherent Close Counter and it didn’t shy away from having both special cooldown acceleration and a conditional spectrum +5 boost on top of it.

Assist: Reposition

Special: Sol / Noontime / Aether

• Healing Specials such as Sol and Noontime are the most effective options for increasing Shinon’s sustainability. In exchange for a longer cooldown, one can also choose to run Aether for a significant damage boost on top of healing. 

Passive A: Unity Skills / Stance Skills / Solo Skills 

• The choice set of A skills if your primary focus is Aether Raids. In addition to the simple +5 boost to the chosen stats, any debuffs and/or Panic effect inflicted on those stats will be reversed to become an in-combat buff. 
  • Keep in mind that this does not neutralize penalties or change your visible stats so AOE Specials will deal complete damage and weapons that are activated based on opponent’s penalties such as Void Tome or Broadleaf Fan will still retain their effects.
• Both Stance skills and Solo skills that boost Shinon’s key stats have their advantages. Stance skills are exclusive to Enemy Phase but come with the added benefit of the Guard effect while Solo skills such as Shinon’s native Atk/Def Solo can be active regardless of who initiates combat and synergize with Double Bow’s condition of not being adjacent to any allies.

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

• Null Follow-up is a strong anti-meta skill that disables any foe's skills that guarantee their follow-up attack or prevents yours. 
• Null C-Disrupt is another highly coveted skill for infantry tanks, as it allows them to retaliate against opponents that would otherwise disable any form of counterattack such as Firesweep weapon users and Dazzling Staff healers.
• Lull skills such as Shinon’s innate Lull Atk/Spd also makes for a solid B slot option by neutralizing buffs on the foe’s target stats as well as inflicting an in-combat debuff. 

Passive C: Smoke Skills / Time’s Pulse / Flexible

• Smoke skills such as Pulse Smoke are very effective when taking on multiple opponents. Pulse Smoke is particularly effective in reducing the damage of opponents around the target after combat by slowing down the activation of their Special.
• The C slot can otherwise be replaced as needed to suit the team. 

Sacred Seal: Spd/Res Solo / Stance Skills / Quick Riposte

• Spd/Res Solo or any Stance skill that boosts Shinon’s key stats makes for an effective Sacred Seal option.
• Assuming you aren’t already using Null Follow-up, Quick Riposte allows Shinon to break through foe’s skills that prevent him from doubling (such as Impact skills) as long as he naturally outspeeds them.

Preferred IV: +ATK or +SPD

Weapon: Double Bow / Firesweep Bow+

• Double Bow makes for an effective Player Phase option as well by granting Shinon a significant stat boost when initiating he’s solo as well as leaving some room for a bit of Enemy Phase combat.
• Alternatively, one can swap to a Firesweep Bow in order to simply make use of Shinon’s strong offensive statline while preventing most counterattacks.

Assist: Reposition

Special: Deadeye / Ruptured Sky / Moonbow

• Since damage reduction skills are meant to represent dodging in normal FE games, what more appropriate skill for erasing them than the skill that guarantees your accuracy in normal FE games? 
• Ruptured Sky (or Moonbow if the former is unavailable) are strong alternatives on the merit of combining a slaying weapon with Time’s Pulse, as there will be no way to stop them from being charged.

Passive A: Impact Skills / Atk/Spd Push or Solo / Swift Sparrow / AR-D Atk/Spd

• Impact skills such as Sturdy Impact are incredibly strong options for a defense team by granting Shinon a significant boost to his firepower and bulk as well as preventing opponents from doubling him in return.
• For more general content or simply for a purely offensive approach, any skill that greatly boosts Shinon’s offensive stats such as Atk/Spd Push or Swift Sparrow makes for a good choice. 
• For the strongest possible boost on Aether Raids Defense, AR-D Atk/Spd can grant Shinon upwards of +10 to Atk and Spd with all buildings active.

Passive B: Lull Skills / Special Spiral / Poison Strike

• Lull skills once again make for a great choice in inhibiting the foe’s ability to buff key stats as well as providing an additional in-combat debuff.
• Once again, Special Spiral makes for a very strong offensive skill by allowing Shinon to activate his Special at a constant rate following the initial activation.  
• Primarily for the purpose of a Firesweep build on defense, Poison Strike allows Shinon to deal additional damage after combat.

Passive C: Panic Smoke / Time’s Pulse / Flexible

• Of all the Smoke skills, Panic Smoke makes for the most effective choice on defense teams by inflicting Panic on target and foe’s within 2 spaces after combat.

• Time’s Pulse is particularly effective on a Player Phase focused build by accelerating Shinon’s instant Special charge. 

Sacred Seal: Swift Sparrow / Death Blow / Sturdy Blow / Heavy/Flashing Blade / Poison Strike / Quickened Pulse

• Any Seal that further boosts Shinon’s offensive power when initiating makes for a great option.
• Similarly, Heavy Blade can be used to have Shinon activate stronger Specials more frequently.
• Poison Strike can be stacked in the Sacred Seal slot for even more damage against the foe after combat.
• Quickened Pulse gives Shinon an additional charge towards his instant Special on defense teams.