Lost powers

Related:
* Lost equipment
* Ill-equipped
* Character transfer

In-game instances are easy enough to notice, start of the game instances are usually equally so but in case the story fails to explain why the protagonist suddenly is having trouble defeating ordinary rats when in the previous game they were capable of destroying whole planets singlehandedly do count for this. However, this requires that the protagonist really is the same person (e.g. Link in Zelda games apparently never is the same person) and the game is a sequel.

In RPG terms, player loses all or significant portion of their levels.

Limitations:
* Level drain attacks from "regular" monsters that can be somewhat trivially restored do not count. Nor do any other temporary status effects that prevent the protagonist from using all their potential.