From publisher blurb:
This document expands the Legacies Organized Play Campaign options to allow players to take and use the Leadership feat in the campaign. A PC with the Leadership is called the “Leader” while the cohort is referred to as the “cohort”. Cohorts can add to a character’s role-playing and they can provide additional services to the party.
However, cohorts are not there to “steal the show” and are members of the support cast. Still they occasionally rise to the occasion and save the day.
In many ways, Samwise Gamgee from the Lord of the Rings trilogy is a cohort: he supports Froddo on his quest.