Over two years on, and before the release of its DLC expansion, it seems that is still housing a few secrets and mysteries, as one fan has uncovered a set of unused voice lines which were apparently hiding in the action RPG's files on PC up until version 1.06. Well, 'unused' might not be quite the right word, as the dialogue itself can still be found in the game now, just not with this voice.
As highlighted by Twitter user @MagicalShion, the lines in question belong to the NPC Nepheli Loux, who has a full questline and can be summoned for some extra help during the boss fight with Godrick the Grafted. In the final version of the game, she's voiced by Cara Theobold, but in these datamined audio files, she sounds very different – almost as if she's voiced by Roderika's actor, Helen Monks, although this isn't actually confirmed. It's not clear why these fully recorded lines were included in the game's files for so long, but it's been by Elden Ring dataminer and cut content restorer Sekiro Dubi that in the Elden Ring network test credits, Nepheli Loux didn't have a confirmed voice actor.
Instead, the credits simply state (translated to English), "to be decided." So, perhaps this was just due to her actual voice actor only getting decided upon relatively last minute. According to @MagicalShion, in the so-called archive "that's not in the 1.
00 build, that includes: Mountaintops with extra recording noise, unfinished versions of Altus, and Mountaintops battle layer, and seven seco.