This is something I have been wondering for a bit. I am currently playing with a Rogue/Warlock Mousefolk build. Here is the link to the Mousekin homebrew race I am playing. I am planning on a build of 12 Rogue/8 Warlock.
As my character is quite small, I wanted to go a stealth/speed route, so I wanted to get the Skulker Feat with the One with Shadows eldritch invocation. To be hidden from enemies would be the main goal of this build, as the campaign I am currently in has a number of encounters. (However, advantage on attack is a second for the bosses.)
So can I hide in dim light/darkness, use OwS, ranged weapon, hide, and then use OwS again? Also, how many actions would it take for me to pull is off? Is this build worth the trouble?
Best Answer
There may be no need for One with Shadows.
To analyze this, we should look at what Hiding (the action) does versus Invisibility.
In the Hiding sidebar (PHB 177), it says
In addition, the condition Invisible (PHB 291, emphasis mine) says
There's a lot of crossover here. The main benefit of Invisibility for this build over "hidden" is that you 1) can always hide, and 2) you always get advantage on attack rolls, which will always trigger sneak attack.
Unfortunately, for this build, One with Shadows ignores point 2, since it's not continuous, so it only gains "you can always hide". This is fully negated by the Skulker Feat, because it allows you to hide in even dim light, and you can't turn invisible with One with Shadows unless you're in dim light. One with Shadows has its uses, but usually not in a rogue, since they can use their bonus action to hide. The only real benefit for this build is that you can hide from enemies with darkvision in dim light, whereas you normally wouldn't be able to, but I don't think it's worth your action in combat, and you should try to find darkness or cover instead.
Action economy with One with Shadows:
Turn 1. Move to dim light or darkness, use One with Shadows, bonus action Hide.
Turn 2. Attack, bonus action Hide, move again
Turn 3. Move to dim light or darkness, use One with Shadows, bonus action Hide.
Repeat steps 2 and 3.
Action economy without:
Turn 1. Attack, move to dim light or darkness, bonus action Hide.
Turn 2. Attack, move again, bonus action Hide.
Turn 3. Attack, move again, bonus action Hide.
Repeat steps 2 and 3.
In the first version, you're guaranteed advantage and sneak attack, but you attack half as much. In the second, you attack twice as much, and will likely get sneak attack, as a creature must actively Search for you to contest your Hide.