Here is a quick tier list based on the Japanese server.
Rerolling
Rerolling in this game is easy. All you have to do is go to the Login Page, tap on Data Management and delete your game data.
However, since you can keep retrying on your first 10x summon, there isn’t really a need to reroll.
Tier List
You should aim to summon at least 2 S rank Monsters with your first 10x Summon.
Note: It is possible to get 3 S Ranks
| Monster | Leader Rating | Member Rating |
 Killing Machine |
8.5 | 9.5 |
 Wight King |
10 | 9.5 |
 Emperor Slime |
8 | 9 |
 Royal Reptile |
8 | 9 |
 Hell Gladiator |
7 | 9 |
 King She-slime |
7.5 | 8.5 |
 Squidzilla |
9.5 | 8.5 |
 Prism Peacock |
8.5 | 9 |
 Archdemon |
8 | 9 |
 Great Troll |
7 | 9 |
 Great Dragon |
9 | 8.5 |
 Hybird |
8.5 | 8.5 |
 Night Clubber |
8.5 | 8 |
 Metal Dragon |
8 | 8 |
 Dragonlord |
8.5 | 9.5 |
 Dragonlord’s True Form |
9.5 | 10 |
 Queen Slime |
7.5 | 8.5 |
List based on Japanese wiki.
