Upgrade Ultimate Skin (not available)

Ultimate Skin of the higher star will receive more bonus in battle, the bonus info of each grade is shown in the table below:
Ultimate Skin Grade
Combat Attributes Bonus
0-Star Skin
Attack +5,000
1-Star Skin
ATK +5,000 DEF +5,000
2-Star Skin
ATK +5,000 DEF +5,000 STA +5,000
3-Star Skin
ATK +10,000 DEF +10,000 STA +10,000

How to upgrade ultimate skin to a higher grade?

Players can obtain ultimate skin of a higher level by upgrading it in Research Center. The upgrade needs to be completed by consuming 3 ultimate skins of the same star. The upgrade is not 100% successful. The probability of upgrade is as follows:
Upgrade to
Success Probability
What you will get if upgrade failed
1-Star Skin
1 * 0-Star Skin
2-Star Skin
1 * 1-Star Skin
3-Star Skin
1 * 2-Star Skin