Fusion Beasts do not appear in the enemy beastiary.
Ok this time its alittle more tricky because now the fusion monster has a higher defense and won't take much damage like last time. So I recommend you get the earth fusion monster and use its special skills because it will cause like 100 points in damge and he will go down in a few turns. Be careful his special skills it may be annoying to deal with
Upon its defeat, the Icarus fusion is unlocked.
Icarus is a figure of the Greek mythology. Son of the architect Daedalus, he was imprisoned with his father as a sacrifice to the Minotaur in the Labyrinth. However, Daedalus used candles to craft wax wings and escape the maze. Even though they succeeded, Icarus was so enthralled in his flight that he went too close to the sun, causing the wax to melt. He fell in the Egean sea and drowned. He's a textbook example of the imprudence of youth when they achieve new capacities, bringing them to their downfall since they don't know their own limits.