Night Hunter (Su): As a standard action, you can blend into the shadows of the night, becoming nearly invisible. As long as you are in an area of dim light or darkness, you are invisible (as per invisibility) to creatures without darkvision. This ability lasts for a number of rounds equal to 1/2 your cleric level (minimum 1). You can use this ability for a number of times per day equal to 3 + your Wisdom modifier.
Stealth > Hide wrote:
Your Stealth check is opposed by the Perception check of anyone who might notice you. Creatures that fail to beat your Stealth check are not aware of you and treat you as if you had total concealment. You can move up to half your normal speed and use Stealth at no penalty. When moving at a speed greater than half but less than your normal speed, you take a –5 penalty. It’s impossible to use Stealth while attacking, running, or charging.
Breaking Stealth When you start your turn using Stealth, you can leave cover or concealment and remain unobserved as long as you succeed at a Stealth check and end your turn in cover or concealment. Your Stealth immediately ends after you make an attack roll, whether or not the attack is successful (except when sniping as noted below).
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Differences:
* Night Hunter does not does not require a roll (and does not seem to rely on the Stealth skill at all, as you noted).
* Night Hunter takes a standard action to activate while Stealth is used as part of another action, typically a move action.
* Stealth allows another creature that suspects your presence to try and locate you with Perception while Night Hunter does not (obviously we are assuming visually, not audibly if you're making noise).
* Stealth restricts you to moving half speed (unless you take a modifier to the Stealth check).
* Stealth can be used with cover or concealment from an observer in any illumination, Night Hunter requires dim lighting or darker.
Invisibility doesn't make you hidden, so you'd still need Stealth for people to not realize you're around. They can't see you, but that's not the same as "hidden", by the Stealth rules. However, being invisible does give you a large bonus to Stealth rolls.
