Bifrost - Defensive war
Marching on the Rainbow Bridge, you found a flock of numerous undead. You threw yourself in a reckless battle to defend the bridge. Thus the defense on the bridge began.
Surprisingly powerful not 1, not 2, but 3 Bosses along with a horde of minions. Obstacle stages make for an 'easy win' situation. Just survive 10 rounds... keep your 3 strongest units blocking the paths and bring 2 healers.