Toughness [General][Fighter]
You are one tough cookie.
Benefit: You gain a pool of temporary hit-points equal to your ECL (minimum 3), which stacks with any other Temporary Hit-Points you may have, referred to as a Toughness Pool. This pool refills after 8 hours of rest. In addition, add your Constitution modifier to your ECL (minimum +1) for the purposes of how many hit-points you regain due to natural healing.
Improved Toughness [General][Fighter]
OK, you can really stand up to punishment. Getting kinda ridiculous, here.
Prerequisites: Toughness, Character Level 6th
Benefit: You may refill your Toughness Pool with 5 minutes of rest. In addition, you gain Fast Healing 1 when below half HP. Finally, add your Constitution modifier to your ECL a second time when determining how many hit-points you regain due to natural healing.
Supreme Toughness [General][Fighter]
OK, stop bragging about how tough you are. It is kinda weird.
Prerequisites: Improved Toughness, Character Level 12th
Benefit: Your Fast Healing from Improved Toughness is increased to 2, and applies at all times. In addition, whenever you refill your Toughness Pool, you may negate a single negative effect that is neither instantaneous nor permanent that you are currently suffering from, removing its effects from you and you alone. Finally, add your Constitution to the amount of ability damage and ability burn you heal each day (minimum +1).
Second Wind [General][Fighter]
Your body reacts well to healing magic. Very well.
Prerequisites: Improved Toughness
Benefits: Whenever you are targeted by a spell of the Conjuration (Healing) subschool, you may refill your Toughness Pool as an Immediate action.