Just like any other RPG game they can smithed your equipment to amplify the stats and making it more effective. In VW they introduce 'The Artisans' these devil Twins can craft any item just give them in their required materials. Once you've collected every collection you will gain good boost up.
FAE WINGS
SPECIAL BONUS:
Gain +10 Attack, +10 Defense, and +20 Energy
Blue Fae Wings
+10 Rage
+20 Energy
Cost: 50 Blue Fairy
Purple Fae Wings
+20 Attack
+20 Energy
Cost: 50 Purple Fairy
Red Fae Wings
+20 Defense
+20 Energy
Cost: 50 Red Fairy
FEATHER WINGS
SPECIAL BONUS:
Gain +10 Attack, +10 Defense, and +20 Energy
Peacock Wings
+20 Attack
+20 Energy
Cost: 100 Blue Feathers
Cardinal Wings
+20 Defense
+20 Energy
Cost: 100 Red Feathers
Phoenix Wings
+10 Rage
+20 Energy
Cost: 100 Red Feathers
DEVIL WINGS
SPECIAL BONUS:
Gain +10 Attack, +10 Defense, and +5 Rage
Black Devil Wings
+20 Defense
+10 Rage
Cost: 300 Black Devil Wings
Purple Devil Wings
+20 Energy
+10 Rage
Cost: 300 Purple Devil Wings
Red Devil Wings
+20 Attack
+10 Rage
Cost: 300 Red Devil Wings
HOW TO GET MORE FRAGMENTS:
1. Do some mission and occasionally some wings may drop.
2. Check your friends gifts and your wall post.
2. Ask for your friend to send over more wings.
4. Use your favor points