User blog comment:Skeith9/Heroic Spirits Speculation/@comment-1458758-20140626150627/@comment-1458758-20140628001947

Yeah, I forgot about Frankenstein, I see how one could confuse that.

Into the Depths was pretty much designed to be a form of presence concealment, in part to make up for his generally lacking ability and in part to make it more difficult for servants with keen senses/extra perceptive abilities to just blow Nautilus out of the water.

And yeah, I'm quite found of his NP myself, very proud of the idea. XD