You can fight back-to-back with an ally, occupying the same space and protecting one another from attacks.
Benefit: You may occupy the same space in combat as a willing ally whose size category is not more than one larger or smaller than your own. While occupying the same space, neither character may be flanked, and each gains a +2 dodge bonus to AC and CMD. If either character takes a 5-foot step, the other character may move with them, but the two may not move together in this way more than 5 feet per round, and any other movement by either of the characters causes them to leave the shared space.
Special: If both characters possess this feat, the bonuses stack, and the characters may move together up to 10 feet per round.
Normal: You may not occupy the same space as an ally in combat.
Undefeatable: The Collected Feats Sourcebook, Copyright 2009 – 2010, Louis Porter Jr. Design, Inc. Undefeated, Copyright 2011, Louis Porter Jr. Design, Inc.