There are three roles for people who manage events: Organization Owner, Admins, and Event Managers.
The Organization Owner is the user that has created the organization. Each community and organization has only one Owner, who cannot be altered. The Owner can't delete the organization but can rename it.
The Owner can invite any user to join the organization. The new team member can be either an Administrator or an Event Manager. The main difference between those roles is that a user with Admin rights can create new events and invite members to the organization, while Event Managers can only edit existing events.