You Do Need power plug adapter while traveling from North Korea to Namibia.

Here is Why You Need An Adapter

The outlet and plug type used in Namibia are D and M and in North Korea is C. This is how they look like.

North Korea

In North Korea, outlets of type C are in use.

Type C

Namibia

In Namibia, outlets of type D and M are in use.

Type D

Type M