Valentine's Líf

Weapon: Þjálfi

Assist: Positional Assist / No Assist / Flexible

Special: Glimmer / Moonbow  

Passive A: Atk/Def Push / Death Blow / AR-D Atk/Def

Passive B: Lull Atk/Res / Wings of Mercy 

Passive C: Fatal Smoke / Cavalry Buffs / Joint Drive Skills / Smoke Skills / Flexible

Sacred Seal: Death Blow / Hardy Bearing / Sturdy Blow / Heavy Blade 

• Valentine’s Líf and Thrasir shine offensively by merit of their phenomenal Attack, effective five-tile range, and absurdly loaded exclusive weapon—and to top it all off, they make for an exceptional Aether Raids Defense pick as they can enable the Duo’s Hindrance structure. A +ATK IV is coveted over all else for maximum damage. 
• For general usage, the Undying Ties Duo can safely use any positioning Assist—but for Aether Raids Defense, the choice is trickier and case-dependent given that it is necessary to account for how the AI prioritizes turn order. Potentially, they can go without one at all to avoid any mishaps.
• Their native Atk/Def Push works excellently for a massive enhancement to their damage and physical durability, but Death Blow 4 is a suitable replacement to squeeze out a bit more of damage. AR-D Atk/Def is another candidate solely for the purpose of Aether Raids Defense, providing a substantial dual phase boost as long as enough structures remain standing.
• Lull Atk/Res provides the greatest overall utility to Líf/Thrasir across all facets of the game—and fortunately comes packed in their base kit—through enemy buff nullification and further stat enhancements. Alternatively, Wings of Mercy may be taken within specific low HP compositions for surprise enemy snipes. 
• Their C skill is quite flexible and will vary on where they are being used. Fatal Smoke is a deadly choice in Aether Raids Defense to punish sustain tanks, but other considerations include cavalry buffs for class-exclusive teams, Joint Drive skills for mutual buffing utility, and Smoke skills when refresher support is available.
• Beyond Attack-enhancing Sacred Seals, Hardy Bearing works excellently to shut down Vantage strategies in Aether Raids Defense—and all but completely destroy Brave Ike combined with Þjálfi’s counter to damage reduction—as does Heavy Blade for faster Specials triggers. 

Weapon: Þjálfi

Assist: Positional Assist / Flexible

Special: Sol / Bonfire / Moonbow

Passive A: Close Foil / Close Counter / Atk/Def Push

Passive B: Lull Atk/Res 

Passive C: Atk Smoke / Smoke Skills / Flexible

Sacred Seal: Mystic Boost / Sturdy Stance / Fierce Stance / Atk/Def Solo 

• This set presents an alternative take to Líf/Thrasir’s typical playstyle for general play, aiming to make the most of their reasonable physical bulk, built-in follow-ups (thus bypassing the need for Quick Riposte), and complementary stat boosts. For their IVs, a +ATK IV once again works well, but +DEF may be considered to reduce physical damage.
• Sol imparts the Undying Ties Duo with ever-useful healing to supplement his defensive capabilities; this allows them to further mitigate damage taken. For damage-oriented options, Bonfire and Moonbow are suitable Specials. 
• Being able to counterattack regardless is crucial for Líf/Thrasir’s versatility, so either Close Foil or Close Counter—whichever is available or preferred—remains their ideal A skills but their base Atk/Def Push is a potential budget skill. Their native Lull Atk/Res is stellar to obtain a greater stat advantage over their foe. 
• Smoke skills bolster their tanking ability through the potent AoE debuffs they apply, with Atk Smoke and Res Smoke are especially notable for boosted survivability and damage respectively. Their Sacred Seal slot—since they have no use for Quick Riposte—can be filled by either Mystic Boost for sustain or anything that enhances the Duo’s key stats.