What is Card Synthesis?

You can synthesize Cards of the Rare and Hero grade Cards in the Cards tab > Card Synthesis.

A random Card of the same grade as the Card used as a material in Card Synthesis will appear, giving the Card some Bonus Stats. There is a low chance that the Card will have a “Special Skill” that gives additional effect.

If you want to keep the same Cards, but reverse the Bonus Stat value and Special Skill chance, you can use 'Priority Card Selection Ticket' item to give a certain material Card an unconditional chance to appear.

You can further increase the chance of a prioritized Card appearing by using the 'Priority Appearance Increase Ticket' item.