From publisher blurb:
The Chain is a group of like-minded warriors who strive to unite the varied races and cultures of the world. Heroic Chain Links work as moderators and peacekeepers. Evil ones wish to unite the world under their own rule.
They wear chain mail and use various chain weapons, such as flails. They share a psychic bond that let them fight as one. They can lend their strength to an ally, and sense if another Link is in danger from a world away.
While many character classes work better complementing other classes in a party, The Chain is unique in that he gets more powerful when there are more of his kind nearby.
This Prestige Class presents you with everything you need to introduce this character into your d20, D&D, or similar RPG. You also get a sample character, 3 new items that complement this character, and 5 story starters to introduce The Chain to your campaign.