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

Here is Why You Need An Adapter

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

Brazil

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

Type C

Type N

Eritrea

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

Type C

Type L