"Night time" mod where the whole game is like the dark Firelink Shrine, you can barely see infront of you and torches are a necessity.

[Cascae]

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[September1863]

Should Be possible since a similar thing was accomplished in Dark souls 2. A texture replacement for the sky box (Something already done by the "Crab" texture mod if Im right) And possibly an ENB or some other lighting overhaul should work.

[Mach1ne90]

http://www.nexusmods.com/darksouls3/mods/136/

This Mod is a Cheat Engine Table, there are 2 "night mode".