Je-Ne-Viv Achievement in Vampire Survivors

Refer to Genevieve Gruyère (5G) for how to unlock this character. Once unlocked, you now need to play as her on any stage and get 100000 kills. Obviously this requires you to also enable Endless Mode, since it'll likely take around 50-60 minutes on the ingame clock to get this many kills. I recommend pairing this run with Rottin'Ghoul (5G) if you haven't unlocked it yet, as you'll unavoidably get the kills for that achievement during this run.

If you want to make it as easy as possible, just play a regular run on Abyss Foscari, and be prepared to spend an hour and a half racking up kills. However, if you're confident in your abilities and weapon selection, go ahead and turn on both Hurry and Hyper to increase enemy density to speed this up. I also grabbed the Skull O'Maniac and Torrona's Box to make this even faster (just be careful you don't die).

My go-to setup is always evolved Santa Water, evolved Axes, evolved King Bible, evolved Lightning Ring, evolved Song of Mana, and then evolved starting weapon.