Re:Monster（リ・モンスター）〜ゴブリン転生記〜 Explanation - Evolution

RE: MONSTER MOBILE GAME EXPLANATION - EVOLUTION

The player unit and certain units can evolve under certain circumstances. In order to evolve into the next form, the following criteria must be fulfilled:

1. Reach level 100 in the current form

2. Participate in certain number of adventures (varying for each form/unit)

3. In some cases, the unit needs to obtain certain abilities by feeding them certain materials.

Do note that only units with ◇ symbol can evolve, with the more ◇ symbols available, the more times the unit can evolve.

Once you've fulfilled the requirements to evolve, a red ! sign will appear on the evolve button

Click on the form to evolve into. Note that you can also devolve into a previous form and retain that form's levels. Particularly useful for the player unit's complex evolution tree.

Evolving costs gold and food. Each form has their own levels to raise.

Lastly, an example of the screen if the evolution requirements are not met. 

In this example, I have enough levels, enough number of adventures (69 out of 20 required), but I have not fed enough materials to him for his evolution, noted by the white boxes. (For this example, in order to evolve Hobukichi, I need to feed him bear claws dropped by Hind Bears, but the game hid the info until he has ever eaten them through the strengthen with materials menu)

Note for the player unit, if the white boxes appear, then you have to eat the materials yourself using the obtain ability menu.