You Do Need power plug adapter while traveling from Eritrea to Brazil.

Here is Why You Need An Adapter

The outlet and plug type used in Brazil are C and N and in Eritrea are C and L. This is how they look like.

Eritrea

In Eritrea, outlets of type C and L are in use.

Type C

Type L

Brazil

In Brazil, outlets of type C and N are in use.

Type C

Type N