Level Enhancement
By using 
Exp Item, you could raise the level of your heroes.
When the hero gains a level, their parameters will increase, excluding their SPD value.
Depending on the rarity of the hero, there is a maximum limit for their levels, which can be increased further by ranking up.
Rank Up
Rank up items can be used to increase the rank of the hero.
By increasing the rank, the max level limit for the hero will also increase.
When the hero reach a specific rank, they get additional ability up and strengthening of the skills.
When a hero reaches rank 5, their illustration will change.
It is possible to revert to the base illustration via the details screen.
There are 2 types of rank up items:
Attribute Rank Up Items
Items needed to rank up the heroes with their matching attributes. You can obtain them through their respective daily quests, and also can be exchanged from the shop using “Laf” currency.
Common Rank Up Items
Items needed to rank up all types of heroes. You could obtain them by Quest Tickets, or to
Hero’s Fan Count Up
You can use the Hero’s Memories to increase the perimeter of the Hero’s Fan Count. Hero’s Fan Count can earn additional View Power during battle.
Relation Enhancement
You can increase the relation by using the 
Training Band. Higher relation level with the sidekick and the hero will have increased perimeter on the hero. Also, sidekicks with a relation level 50 and higher and higher with the hero will gain a special skill, known as the Equipment Skill.
Sidekick’s Limit Breakthrough
You can use the Sidekick’s Mind to raise the relation limit with the hero. Also, the strength of the sidekick’s skills increases after a set amount of limit breakthroughs.