Amazon Relational Database Service (Amazon RDS) for MySQL now supports rds_superuser_role to simplify implementation of role-based privileges on MySQL 8.0. The rds_superuser_role is granted by default to the primary administrative user, and has privileges including, CREATE ROLE, CREATE USER, and DROP ROLE, for all database objects. For a complete list of rds_superuser_role privileges, refer to the Amazon RDS User Guide.
Source:: Amazon AWS