There is a way for Cyan to attack continuously until all enemies are dead:

Step 1: Kill Cyan in battle.

Step 2: Revive him again (Best is you equip the relic Knight Code Relic on someone else to protect him).

Step 3: Have Cyan use his Level 2 Bushido, Sky.

Step 4: Quickly cast Imp on Cyan, or he might attack with Sky even there's no enemy attacking him! (Sky is used and it is wasted, so it is recommended that the person which cast the Imp is directly right after Cyan's turn on using Sky).

Step 5: Wait for a short while, and get ready to pull your hair in surprise as Cyan strikes the opponents,until all is dead.

How did it happen? Well, as you kill and revive Cyan, the game is actually thinking that the enemies is attacking Cyan non-stop by that time, so Cyan automatically use Sky right after you use it, that's why the casting of Imp's timing must be perfect.

Secondly,as you cast Imp, it made Cyan use Sky, yes, but this time, the Imp spell had made the game move, Sky, a bit jumbled up. Why Cyan attack continuosly is that Cyan is actually countering his own attacks!