Grand Hero Battle - Clarisse

5* Kagero with LnD 2 and Attack seal
5* Cordelia with Tri Advantage 3, Aether and Speed seal
3* Olivia
5* Olivia
First Turn;
1. Position Cordelia opposite wall section to be destroy.
2. Position 1 dancer on her right.
3. Position 2nd dancer above right second dancer.
4. Position Kagero above 2nd dancer, destroy wall and then dancer her right.
Second turn:
Red fighter dies by Cordelia, Cordelia attacks Clarisse twice with Dancer, Kagero finishers her off. Dance Cordelia to attack Green mage twice, then dancer her to attack Dagger, then Aether turn to finish Green mage.
Third turn:
Cordelia attack Blue mage.

Notable skills :
Nowi : Defense+3, Quick Riposte, Pivot, HP+3 Seal
Tharja : + Attack nature, Moonbow and Quickened Pulse seal
Kagero : Death Blow 2 (mine is not optimised at all and had poor nature so any Kagero helps immensely here), Anti-Dagger 3, Attack+1 Seal
Sharena : native buff skills + Fury / Renewal, Seal Res

I don't break the wall at the center of the map. On turn 1, Nowi is boosted in Def and Att by Sharena, survives and hurts both Clarisse and the Thief.
Then Kagero kills the Thief and Tharja the Green Mage Rider, with Nowi Pivoting to keep them from harm if needed. Kagero is really useful for the last 2 soldiers too.
Be very very cautious, the positioning must be really precise and all your units end up having low HP. So try to avoid any unnecessary damage in the first turns, namely by putting Tharja out of the debuffing range of Clarisse's weapon.

Yes, I got this team by being a F2P and skill inheritance
Also let Hector tank the Green Mage and Clarisse, then send Hector back and let B. Cordelia brave bow everybody to death.

Xander is great to lower the ninja's hp and kill the green tome in the same action, put him in range for clarisse so he lowers her hp as well, be aware to back down constantly, and when she's close, lower her hp even more and finish off with elise, don't remember how i killed the blue tome but he must to be dead by now, put Xander in a place where the red cavalier and ninja can't attack other units, but Xander has to have some hp left tho, because the red cavalier does like 6 damage, and the ninja does 0 damage, kill the ninja off in the next turn and use reinhardt to finish the red cavalier, it was pretty ez

vantage ryoma +5hp
vantage hector +QP (draw back)
Kami Reinhardt (moonbow)
Waifu Azura

The setup (bottom left to top right start)
ryoma hector reinhardt azura

ZA BAITO!
break wall using reinhardt. dance him and move top right tile above azura. this baits red unit to attack ryoma and the other units to move. kill red with ryoma, move hector one tile up. move reinhardt lower tile right below hector. this causes green mage to die to hector.

THE ASSAULT.
use reinhardt to kill red sword. move hector beside ryoma. ryoma reciprocal aid hector. dance reinhardt and kill condescending bow whore. make sure azura dances the left side. and safe from ninja. ninja should be out of fort space. use reinhardt to kill him. ryoma/azura wombo combo blue mage.