Creatures can be reborn to level 1 for either a Credit or Coin cost to gain greater stats than a Superb. Currently this is a Credit Shop option that can be accessed here.
Please remember that Rebirthing will never turn a creature Superb quality. A Great at a Rebirth level of 99 will have .5 stat points lower than a Superb at Rebirth level 99.
A creature must meet the following prerequisites before it can be reborn:
Rebirth level will be added to the creatures quality during stat calculations. This can improve its base growth to a level even higher than Superb depending on its original quality. For example, you would have to rebirth a Great creature twice to have the growth needed to top a Superb.
For example, a Superb with a Rebirth Level of 5 will receive 5 points to each attribute at level up instead of 2.5 like a normal Superb.
The following things will happen to a level 99 creature if it is reborn:
A creature's tattoos, equipment and skills can be retained during rebirth if you acquire the Credit Shop Key Item Four Arms of Vishnu.
Please note the following:
The amount of experience needed to level up will increase by 5% per Rebirth level. So a creature that has a Rebirth Level of 5 will require +25% more EXP to reach level 99.
Note that when a creature reaches Rebirth Level 125, the EXP requirement will become more drastic and dynamic.