おわりのだいち (Desolate Land)

Desolate Land is Primal Groudon's signature ability that establishes an incredibly powerful weather condition known as extremely harsh sunlight. Upon entering battle, this ability immediately sets the weather to this enhanced sun condition, which retains all the standard benefits of Sunny Day while adding the devastating effect of causing all damaging Water-type moves to completely fail. This creates an impenetrable shield against one of Ground-type weaknesses, fundamentally altering the dynamics of any battle involving Primal Groudon.

The ability's weather control is nearly absolute, as extremely harsh sunlight cannot be overridden by typical weather-changing moves or abilities. Only the equally powerful Primordial Sea and Delta Stream can replace this weather condition, creating an interesting rock-paper-scissors dynamic between the three primordial weather abilities. When Primal Groudon switches out or loses this ability, the weather immediately returns to normal, making its presence on the field crucial for maintaining the effect.

In competitive play, Desolate Land transforms Primal Groudon into one of the most dominant restricted Pokemon, completely shutting down Water-type attackers while enabling powerful Fire-type moves from teammates. The ability's interaction with Air Lock and Cloud Nine is particularly noteworthy - while these abilities prevent the weather effects from activating, they don't actually change the weather itself, creating unique strategic considerations in team building and battle scenarios.