Merlinus

Weapon: Goodie Boot(+DEF) / Goodie Boot(+RES)

Assist: Positional Assist

Special: Bonfire

Passive A: Mirror Stance 2 or 3 / Sturdy Stance 2 or 3

Passive B: Chill Atk 3 / Chill Def 3

Passive C: Distant Guard / Preference

Sacred Seal: Distant Guard

• This build lets Merlinus shine in a supportive role, since he doesn’t have to try fighting with his 20 base Attack and can instead let a much more capable unit such as Roy or Tanya do the fighting in his stead. However, as a support unit there’s nothing Merlinus can provide that superior support units cannot.
• Goodie Boot provides Merlinus some additional defensive stats in combat on the off chance a player phase unit gets danced and reaches him from across the map. If you can’t deal any damage, you can at least live to 0x2 another day, right?
• Mirror Stance and Sturdy Stance 3 provide Merlinus some extra insurance in combat by granting him the Guard effect, which helps keep him safe from the Enemy’s special triggers. Mirror Stance and Sturdy Stance 2 can also be used on a budget, although they lack the Guard effect.
• Chill Skills let Merlinus support his team further with their debuffs, although they can still be turned against him with Debuff absorption skills such as Chaos Ragnell.
• Lastly, Distant Guard in both the C slot and Seal allow him to grant a massive boost to his allies defenses when they fight ranged units. 

Weapon: Broadleaf Fan(+DEF) / Minty Cane(+DEF)

Assist: Positional Assist

Special: Bonfire

Passive A: Close Foil

Passive B: Lull Atk/Def

Passive C: Joint Drive Atk / Panic Ploy Preference

Sacred Seal: Close Def / Sturdy Stance / Mirror Stance

• This build aims to “redeem” Merlinus’s 20 base attack and let him occasionally deal more than 0 damage when he fights. With a buff he might even get a KO or two before running into a Brave Edelgard and crying.
• The Broadleaf Fan allows Merlinus to deal additional damage to debuffed foes, giving him some means of dealing damage. However, his base 20 Attack makes him completely reliant on its effects, and without it, he’s a sitting duck. This leaves him helpless against debuff nullification effects such as Restore and Pale Breath, as well as debuff absorption such as Fallen Ike’s Chaos Ragnell and Atk/Def Unity. Minty Cane can also be used, but Merlinus’s damage output will tank completely as a result unless the foe’s defense is also low(not that it existed to begin with).
• Bonfire, Close Foil, and Lull Atk/Def give Merlinus desperately needed attack power, although even these likely aren’t enough to save him from his base 20 Attack. However, Close Foil and Lull Atk/Def at least give Merlinus some extra bulk, making him deceptively tanky thanks to his high HP. His middling Defenses render this moot, however.
• Joint Drive Atk allows Merlinus to support a much better unit such as Mareeta with additional killpower. It gives him some extra offensive power as well, but that doesn’t matter much thanks to his 20 base Attack. One can also make use of Merlinus’s high HP with Panic Ploy if desired.
• Lastly, Defensive Sacred Seals such as Close Defense work well as they help Merlinus tank some extra hits and deal a smidge of extra damage(1x2 instead of 0x2).