D&D 5E Fighting with Darkness?

[xynthoros]

So a third level warlock can have the darkness spell and the ability to see through said darkness spell. If two levels of rogue are taken first followed by the three levels of warlock, you can have two attacks with your pact weapon at fifth level. Darkness essentially grants advantage on all your attacks and disadvantage to all attacks against you, at least against most enemies. The question I guess I'm posing is, would such a build be feasible? Would there eventually be so many enemies with true sight/devil sight to make the build useless?

What feats/ability boosts would be recommended? I imagine dex to 20 ASAP, but then really only feats matter. Which pact would be patron would be best? 5-6 temps every kill isn't much but it might make a decent buffer over the course of a day, mass charm/fear could be useful if you can bump the save high enough, one way telepathy isn't bad for a stealthy type either.

Would the second attack form pact of the blade really matter? Would having an unlimited range invisible scout who I can cast my senses through be more useful?

 

[Zaruthustran]

That combo has become a classic Warlock build path, and some builds use it (the three-level dip) as a foundation.

The second attack is useful in that hey: more attacks, but keep in mind Sneak Attack can only be applied once per turn.

Personally, I'm a much bigger fan of Pact of the Chain. The invisible, senses-projected scout is just astoundingly useful, and essentially combines several high-level spells into a permanent & re-summonable-if-killed package.

 

[Llokii]

The 2nd attack isn't available until Warlock level 5, not combined level 5.