Unit Upgrade

Experience
Units earn Experience through clearing Missions (except for some certain Special Events). Player can also use various types of Experience Cards to increase a Unit's Level.

There is a level cap for each Grade (★):
 * 1★: Lv35
 * 2★: Lv40
 * 3★: Lv45
 * 4★: Lv50
 * 5★: Lv55
 * 6★: Lv60

Remodeling
For each remodeling upgrade, player will need six unique parts of a certain quantity. The quantities required range from 1 to 25. Most of the parts can be obtained through Normal Mission. For a few rare parts, the drop rate tends to be low. But sometimes player can get them from Events or Special Missions, whether through clearing them or exchanging them in Event Point Exchange Booth. As of July 2018, the highest Remodeling Version is 14. It can be observed as a light blue background with gold triangles on the Unit icon.

Skills
Each unit has five skills. Player can upgrade each skill with Coins. By default, each Unit comes with Skill 1 and a Special Skill. As the unit level up to a higher Remodeling Version, new skills get unlocked, as follow:
 * Skill 1: Unlock with Version 2
 * Skill 2: Unlock with Version 4
 * Skill 3: Unlock with Version 7
 * Skill 4: Unlock with Version 9
 * Special Skill: No lock, available from Version 1
 * Special Skill 2: Only through special Events. Usually player can only unlock it by achieving a rank of 10,000 or higher in Arena end of the season.

EN (Energy)
EN is the energy that is needed for a Unit to utilize its Super Move. In battle, it is represented by a yellow bar on the bottom of the Unit's square card. It is very important as most Unit's Super Move is a lot powerful than its regular ones, and for some Units, their Super Move targets enemy's team globally (Global Attack).

EN Tanks are used to upgrade a Unit's energy bar in the beginning of a battle. Each stage of EN upgrade grants a percentage of EN filled in the beginning of a battle.