You choose one specific field of knowledge and the maladies encompassed by it, and by focusing on that field, you are able to use your knowledge exclusively to resist those maladies.
Benefit: When you take this feat, choose one Knowledge skill which you have improved with the Skill Focus feat. Whenever you make a Fortitude save to resist an effect encompassed by that Knowledge skill, you may use your Knowledge skill check in place of your Fortitude save bonus to resist the effect. For example, Knowledge (arcana) would allow you to resist effects created by dragons, constructs, and magical beasts in this way. Refer to the Knowledge skill list for the topics covered by each knowledge skill.
Undefeatable: The Collected Feats Sourcebook, Copyright 2009 – 2010, Louis Porter Jr. Design, Inc. Undefeated, Copyright 2011, Louis Porter Jr. Design, Inc.