|This build centres itself around making Merric utilise his new gains from the 2.0 update, allowing Weapon Refinery. Notably the greatest addition to his arsenal is the formerly Sonya exclusive Dark Excalibur, essentially a Green Tome Wo Dao. Considerably less situational than his previous Excalibur, of which did bonus damage to fliers, he can now boost his moderately low Attack by an extra 10 damage output each time his special activates. Since he is also more bulky than your average mage (though still a far cry from Boey in that regard), this build aims to find a use for a spare Takumi you may have around and utilise his superior bulk to most mages.
His weapon, as stated earlier, is his newly available Dark Excalibur.
While his assist is indeed flexible, Reposition and Draw Back are the recommended ones.
His special can go one of two ways. If you wanted more damage output, Moonbow works fine and will activate every round of combat due to Quick Riposte. However if longevity is a concern, Noontime recently recieved a cooldown reduction and this can help Merric remain in Quick Riposte range. This is further aided from the Wo Dao effect of Dark Excalibur boosting his damage output and increasing HP recovered.
His A skill is Close Counter, as this lets him retaliate on Enemy Phase on all enemy units.
The B skill, though Quick Riposte is what most would take forward, is indeed flexible. Renewal can be taken forward for, again, longevity. Additionally if you wanted a wider activation range against a more likely foe, then Blue Tomebreaker or Lancebreaker both work as well. It is worth noting that Quick Riposte 2 works fine enough if Quick Riposte 3 is not available.
The C skill is recommended as Threaten Atk 3 as this aids his ability to tank via enemies dealing less damage. Though this is indeed not the only option, a spare Luke or Valter allows for Panic Ploy to be a decent option if HP is not Merric's bane. Otherwise, a simple Spur, Hone, Fortify or Drive skill does fine.
The Seal is very highly recommended to be Close Def from the Less than Heroic Tempest Trials, as this gives Merric more durability against foes Close Counter allows him to face. However if this is not possible then Defense +3 or the equal Squad Ace B works well enough.
While this build does require heavy investment, it is what can be considered a suitable way to use Merric's new capabilities.