Boey

Build intending to make Boey a very heavy hitter while maintaining and improving his base bulk, and even improving his allies' bulk. The key factors in this are his A and B passive skills, as well as Gronnowl. The niche of this build seeks to have Boey surrounded by allies most/all of the time, increasing all of his stats by another 6; practically a Fury 3 without the HP cost! In a +atk/-res nature, which is optimal for this build, Boey will reach the following statline at 5-star Lv40: 48 Atk, 33 Spd, 38 Def (same as Hector!) and 24 Res. His allies will also get a +3 buff to Def and Res. He'll be able to double some slower enemies already, but Quick Riposte allows him to double anyone who attacks him over the 70% HP threshold. With his insane Def, this can be maintained easily after multiple assaults from any physical attacker aside from sword users, but Reciprocal Aid allows him to stay within that range. Bonfire gives a guaranteed 19 damage boost to his damage. Alternatively, should the player desire, Ignis deals even more damage at the expense of one more turn. The Sacred Seal preferred for this build is Breath of Life, as it allows him to even heal his allies on top of the +3 to Def/Res.

Pseudo healer

A Spd boon Boey can still be useful.
With 30 Spd + Darting Blow 3, he can double attack anyone with 31 speed or less.

Gronnowl+ is used so that Boey's stat increase with each ally around him (additional +2 Akt/Spd/Def/Res per ally).

Since Boey benefits from having allies around him, Breath of Life 3 works as a Passive C. Breath of Life 1 S-Seal bumps the total healing to 10 HP.

To complete the pseudo healer, we use Renewal 3 and Ardent Sacrifice (or Reciprocal Aid if you need to heal more than 10 HP at a time).

[4* at Lv 40+10 with +Atk/-HP]

Recommended Seal: Quickened Pulse, Speed +1

Ignis works too, but only if initiating - plus, it lands him fewer kills than bonfire due to his mediocre speed.

Anti Archer build.

Boey is probably the worst unit from Celica's banner. My friend really believes he is trash. I think he's an understated character.

Gronnowl is used because we're too damn lazy to change it. Plus this build will be mostly centered around it. Although for more a anti bow build, using Gronnraven is recommended.

Draw back has good synergy with Gronnowl. Have another unit with draw back to fully use Gronnowl's buff.

Ignis is OP. Especially on units like Boey with high defense. 26 extra damage.

Earth boost is used to boost Ignis by 3 and is good for defense purposes. Because Archers/daggers probably have lower HP than Boey, Earth Boost is reccomended to improve on tanking their hits. With this Boey can not take damage (or take little damage) from units like Takumi and Klein. Triangle Adept is reccomended if you're using Gronnowl to fully nuke archers.

Bowbreaker will mean Boey will survive an attack from Brave Bow Brave Lyn. That's major in meta game. You can also keep his renewal but keep in mind that Boey will not be able to survive Brave Lyn.

Fortify Def will work great with Draw back, and Gronnowl. This will mean your buffer, draw back, then counter with Boey can add 4 defense to your buffer and!!! If the archer attacks your buffer, they have a greater chance of survival.