Marianne

Weapon: Icy Fimbulvetr

Assist: Positional Assist / Flexible

Special: Iceberg / Sol / Noontime / Glimmer / Moonbow

Passive A: Atk/Res Unity / Atk/Def Solo / Atk/Res Solo / Mirror Stance / Close Foil 

Passive B: Lull Atk/Res / Null Follow-Up / Special Spiral / Null C-Disrupt

Passive C: Smoke Skills / Joint Drive Res / Flexible

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

• Marianne’s access to innate healing, follow-up attacks, and a powerful stat swing alongside her highly specialized statline allow her to shine defensively. This is especially true within the context of Aether Raids Offense, as she is well-suited to combat the heavily magic-leaning nukes that tend to occupy Defense teams. A +ATK or +RES IV will generally be her preferred options to further develop her statline’s inherent strengths, but +SPD and +DEF may also be situationally useful in AR-O. 
• Healing Specials make for a natural choice to supplement her tanking ability through a consistent source of sustain; such Specials are particularly useful at lower merge levels if using her to directly soak physical damage. However, since Icy Fimbulvetr already provides useful on-hit healing, Marianne does have the flexibility of equipping a Special like Iceberg for enhanced damage instead.
• Realistically, any A skill that enhances Marianne’s Attack and Resistance (or potentially Defense if running her as a superunit) will work well here. Solo skills are the most generally useful as they grant the greatest amount of stats and come with dual-phase functionality, but Unity and Stance skills may be worthwhile if available to work around debuffs and enemy Specials respectively. Close Foil and Close Counter are other options for a more traditional tanking playstyle, allowing Marianne to counterattack regardless of range; however, these require considerable merges and/or support to pull off given her abysmal physical bulk.
• Marianne’s B slot is quite flexible as well given her abundance of options as an infantry unit:
  • Her native Lull Atk/Res couples wonderfully with the Attack/Resistance debuff she already applies on her foe through Icy Fimbulvetr, and its ability to nullify enemy buffs to these stats is particularly useful for general play. The usefulness of this does drop considerably in Aether Raids Offense, though. 
  • Null Follow-Up is an exceptional alternative to grant Marianne a great deal of versatility in the threats she can shut down; by granting immunity to ubiquitous effects that would hinder her follow-up or guarantee that of her foe, this skill simultaneously grants offensive and defensive benefits. 
  • If Sol is her chosen Special, Marianne can equip Special Spiral to trigger it on her first counterattack in each combat after its initial activation, allowing her to fully maximize its healing benefits. 
  • Null C-Disrupt is another potential candidate to counter Dazzling Staff and Firesweep-weapon users that might otherwise prove difficult to bait. This is highly recommended if aiming to use Marianne as a counter pick for cavalry lines in Aether Raids Offense. 
• Smoke skills are one of the prime recommendations for Marianne’s choice of C skill due to their synergy with a defensive playstyle, though her Joint Drive Res can always be kept to directly pad her magical bulk. Aside from stat-enhancing Sacred Seals (preferably in the form of a Solo or Stance skill), the Mystic Boost Sacred Seal also works well here.

Weapon: Icy Fimbulvetr

Assist: Positional Assist / No Assist / Flexible

Special: Iceberg / Glimmer / Moonbow / Ruptured Sky

Passive A: Sturdy Impact / Atk/Def Solo / Death Blow / B Duel Infantry

Passive B: Lull Atk/Res / Null Follow-Up / Special Spiral 

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

Sacred Seal: Atk/Def Solo / Death Blow / Sturdy Blow / Mirror Strike / Heavy Blade 

• Thanks to her stellar Attack, in-combat debuffs on her foe’s Resistance, and automatic doubles, Marianne boasts an exceptional damage ceiling and can perform quite well as a traditional offensive nuke. Taking her four-point +ATK IV is naturally recommended to frontload as much damage as possible. 
• Iceberg scales well with her innately high Resistance, granting considerable burst damage on top of a reasonable three-turn cooldown; it can also be paired with Heavy Blade to activate in each round of combat, provided her opponent can counterattack. For more frequent activations, one of Glimmer, Moonbow, or Ruptured Sky should be taken for their short cooldowns. 
• Sturdy Impact is by far Marianne’s ideal choice of A skill for offensive purposes; on top of an ample damage increase, its substantial Defense boost and negation of her foe’s follow-up attack greatly improves her performance against physical units. Atk/Def Solo and Death Blow are suitable alternatives if this is unavailable but if aiming to invest minimally, her base B Duel Infantry can simply be kept. 
• Marianne’s default Lull Atk/Res imparts a significant offensive edge through its concurrent enhancement to her damage and survivability, inflicting further in-combat debuffs on her foe’s Attack and Resistance while also nullifying their buffs. Alternatively, Null Follow-Up may be taken to ensure her follow-up attack—a crucial aspect of her offensive capabilities—or Special Spiral to leverage higher cooldown Specials. 
• Her C slot is flexible and can easily be filled by anything that benefits her team, such as her native Joint Drive Res. That being said, for specific recommendations, Smoke skills are always solid when provided with refresher support and Time’s Pulse contributes to Marianne’s damage by letting her access her Special faster. Any Sacred Seal that boosts her Attack will work here.