Bound Hero Battle: Alm & Celica

Reinhardt with Dire Thunder, Goad Cavalry and Death Blow
Azura with Sapphire Lance and Fury
Leo with Rauorblade , Quick Riposte and Fortify Cavalry
Cecila with Gronnblade and Hone Cavalry

Sanaki : Draw Back, Fury 3 / QR 2
Standard Azura Dancer
Takumi : Brave Bow+ / LnD3 / Axe Breaker 1 / Threaten Spd 3 / Luna
Reinhardt : Draw Back / Death blow 3 / Red Tome breaker

1- Sanaki bait the green mage
2- Takumi kills the lancer
3- Takumi kill the blue mage, Azura dance for him, Takumi kills the axe.

Some draw back to keep your Takumi out of Celica's range.

4- Reinhardt kills Celica
5- Takumi kills Alm

I guess you need some good placements in order to win this. But it's possible.

No merged units
Ryoma +speed L&D2 Reposition (other slots dont matter)
Ephraim +atk Blue tomebreaker Honespeed 3 rally def fortify res seal (other slots dont matter)
Nino +speed Greenblade+ Draw Back Hone atk 3 (other slots dont matter)
Rein Neutral Atk+3 Red tomebreaker Luna Reposition (Other slots dont matter)

1) Bait Green mage with ryoma (he needs hone speed buff to kill it) , put Ephraim under ryoma and put nino right to Ephraim, Rein on the right bridge;
2) Ephraim rallies nino that kills blue lancer, move rein to one tile up and right, ryoma repositions Nino on the bridge;
3) Ephraim kill blue horse mage, ryoma kills green flier and Rein goes up killing Celica and putting himself between ryoma and Alm (Rein will take around 7 damage by alm)
4) Just bait Alm and finish him off with Rein and Ephraim

Key of the strategy is to assign QR (1, 2 or 3) to Sanaki, just simply bait the green mage with Sanaki.

She will slap him back twice, the rest is easy. Ursula will tank Celica & Alm after one shoot the blue horseman.