Upgrading characters is a way to make it gain experience faster and allow it to use higher level isekais. The higher the characters rarity, the higher the tier it can gain. A 1-star character can get maximum tier 1 while a 6-star can get maximum tier 6. See below for the boosts it gives.
im.upgrade [local id] or im.u [local id]im.u 231Once you upgrade a character it is irreversible.
7-star and higher characters which are obtained from boosting/donating/giveaways can be upgraded to tier 5.
| Tier | Level | Exp Multiplier |
|---|---|---|
| 1 | 100 | 120% |
| 2 | 150 | 140% |
| 3 | 200 | 160% |
| 4 | 250 | 180% |
| 5 | 300 | 200% |
| 6 | 350 | 240% |
Upgrading a character will revert it to level 1.
You need the previous tier at indicated level to upgrade, example: To upgrade to tier 4, you need a character at tier 3 and level 250 or above.