From publisher blurb:
Fellowship is a game for 3-6 players about going on an adventure, in the same vein as Lord of the Rings or Wakfu or Jojo's Bizarre Adventure: Stardust Crusaders. The system is loosely based on the Apocalypse Engine. This is the second book in the Fellowship line, an expansion to the first game. You will need the first book to play with the content found in Book 2.
Inverse Fellowship is a follow up to both Fellowship and Inverse World. Within this book, you will find 7 new Fellowship playbooks, a replacement Overlord playbook, and a new kind of playbook, a Team playbook, used by the entire Fellowship cooperatively. There's also a slew of new Destinies, Threats, and Set Pieces, as well as a chapter discussing the Inverse World and what you can find there.
The Horizon is an alternative to the Overlord playbook. Rather than heroically stopping the end of the world, the Horizon lets the fellowship play as explorers pushing out beyond known society, discovering what lies in uncharted skies. Rather than making a single big boss and their minions, the Horizon builds unique Locations that grow more dangerous the longer the fellowship spends there. The Horizon also keeps track of what each player wants to find and uses the knowledge to tempt them. By combining increased temptation with heightened danger, the Horizon can put an end to the most powerful of heroes, through their own greed.