Master of Darkness Feat

[Milo v3]

In the 3rd party Book of Roguish Luck it has a feat called Master of Darkness, only prerequiste is a 14 dex score, with the benefit of: "Creatures with darkvision cannot see you when you attempt to hide in shadows." With the feats only drawback being that it doesn't work in an anti-magic field.

Technically by RAW, you don't even need a hide check to be invisible to creatures with Darkvision if you try and hide in the shadows with this feat. But RAI is pretty obvious, and what I'd prefer to talk about.

If this feat can be accessed in a game, wouldn't every single creature that uses stealth take it? It seems to be a Feat Tax if it exists in the game.

[Jeff the Green]

When a feat can be duplicated with a 6,700 GP item (Ring of the Darkhidden), it's a sucker's bet.

[Cog]

If this feat can be accessed in a game, wouldn't every single creature that uses stealth take it? It seems to be a Feat Tax if it exists in the game.
Whether something is a feat tax isn't an argument against the feat, it's an argument against the base mechanic that needs a feat to patch it - in this case, the Hide skill. Many uses of skills have a -2, -5, or -10 to the check for special circumstances, and hiding versus unusual senses probably should have been handled like that.

As for the feat in question here, there's an official feat - Darkstalker, from Lords of Madness - that covers similar territory.

[Mr Adventurer]

Compare Darkstalker.

[Big Fau]

When a feat can be duplicated with a 6,700 GP item (Ring of the Darkhidden), it's a sucker's bet.

And said item being arguably better if you have a way to cast Darkness at will (and can see through it yourself of course).

[LTwerewolf]

Compare Darkstalker.

This. Darkstalker is all manner of better.

[Urpriest]

Hiding in shadows isn't actually a thing that anybody except Shadowdancers can do. You can hide in concealment, yes, and yes, darkvision obviates certain types of concealment...but phrasing it as "hide in shadows" makes you think that there is some sort of specific "hide in shadows" ability, which is true of other games but not of D&D. Basically, if a third party rulebook is going to avoid actually writing rules in rules language, it's likely there are worse errors elsewhere.