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ShurikensMiner

Hero Stats

HP 40
ATK 38
SPD 29
DEF 32
RES 23
Boon+ Atk Bane - HP

Skill Set

Hero Build Overview/Explanation

This build turns Donnel from a humble farm boy into a Player Phase Force of Nature. This Donnel, especially when Merged, has an insane attack stat on Even Turns. A +10 Donnel with a Boon in Attack will have 80 attack on Player Phase even turns, and 61 Defense. His Resistance will be kind of low, but that doesn't matter when he's guaranteed to attack twice before the enemy can counterattack. The only units that are going to survive that are units with insanely high defense, or insanely high HP. And since the highest defensive stat for any magical unit is Dheginsea at 41, this Donnel Build won't need to worry about healing, and even when he *does* need to heal, he has Aether, which absorbs half of the damage he deals as HP.
The only threats he has to worry about are Enemy Phase Mages, as his Resistance is middling at best, which can be negated by having an ally with a Far Save skill, preferably someone like Brave Hector or Nagi with an Attack/Res Far Save skill (Nagi especially since she has Distant Counter as an A Skill, her res is the highest of any Armored Unit, and her C Skill is easily replaceable anyway). Enemy phase physical attackers are also a possible problem, but if this Donnel is used right, there won't be any physical attackers to worry about by turn 3.
The B Slot is left Blank, as it's mostly filler. You could add a Lull Def skill on there, or you could add Lancebreaker, or Swordbreaker, or really anything. Defense Faint would be useful as they'd make his actual attack 87 instead of 80 on even turns, but that would require a Rally Skill to be used on him.
Similarly, the Assist Slot is also blank, as he's meant to be the driving force, and since he's a player phase force, he wouldn't work well with something like Pivot or Reposition.
Overall, this Donnel is going to be incredibly strong against almost any unit. The best possible team I personally can think of for him is

Donnel
Atk/Res Far Save Nagi with a Rally Skill
Any Dancer (So Nagi can still catch up with Donnel to activate Atk/Res Far Save)
A Good Healer (For Nagi, or Donnel if drastic measures are needed)