Someone did it for the first Dark Souls on PC, so of course it was going to happen for Dark Souls II.
https://kotaku.com/dark-souls-looks-even-more-terrifying-in-first-person-967869774
https://www.youtube.com/watch?v=pBtk6rOGmpU
What you’re seeing here is a hack that “tells the game’s camera to permanently stay zoomed in, giving you a first person perspective”. Technically, aside from a few little glitches, it works just fine. But in terms of difficulty and design…Dark Souls II is a game reliant upon timing and your positioning in the world relative to your enemies, so this is going to make a tough game tougher.
Still! If you want to try it out, there are download links in the vid description here