Yandere Queen (Runner Up)
Disclaimer: This article requires an understanding of the premise for both Dangoranpanga and Mirai Nikki; many points made reference content from both series.
Let's start by clarifying who the queen of Yandere is. This is hands down without a doubt, the undefeated champion, Yuno Gasai. If you're one of the few asking "Why Yuno Gasai?" well then strap on in because I'll tell you. In a brief summary she quite literally created a rip in reality... twice (referencing OVA), a multi-verse, destroyed two universes and became A GOD; all for the love of a guy. A guy mind you, she rarely spoke to. So the title Queen without a doubt is awarded to Yuno Gasai.
Now the runner-up is up in the air. I may need to brush up on my anime experiences but the amount of yandere's that contend with senpai Gasai is few and far in-between.
Yandere list in no particular order:
Albedo: Would kill literally anyone that wants Ainz Ooal Gown if he'd let her. Someones co-dependent. Oh and she also dry humps everything on his bed when he's away, not to mention the number of times she's tried to fuck him.
Shirai Kuroko: Sissy complex, let's not forget the hoard of recordings, she also has an issue with dry humping Misikas beds. Lets not even begin with how she became her roommate.
Shion Sonozaki: Fuck this anime was confusing, which life was it that she was crazy again?
Mana Ouma: Wait wasn't that her brother? She also "almost" destroyed the world, maybe 3rd place.
Rena Ryugu: There's really only room for one yandere in one anime, thank you!
Anna Nishikinomiya: She came in his cookies, I stopped breathing I laughed so hard.
Lucy: She killed EVERYONE she saw over his cousin complex, poor Nana.
Now that we've got that list out of the way the one character I haven't seen discussed was Junko Enoshima, I've read quite a lot of fandom forums filled with other opinions on yandere's but time and time again Junko's name remains absent; this is a stretch but it's such a fun one!
No, if we're going with the literal definition of Yandere than technically Junko is not a Yandere... to an individual, but if despair was personified as an individual than yes she is. If we're getting all philosophical here; a yandere is just a state of mind, a serotonin or dopamine spike she/he experiences from usually an individual BUT Junko surpasses that. She is "enlightened" and instead experiences this through her obsession and infatuation with despair.
Danganronpa already personifies despair as DesBear ( the best pun in anime history by the way, and it's terribly underrated.) All throughout the series, the bear is the ringleader, until Junko is exposed, so the idea isn't that far of a stretch. She psychologically manipulated and murdered her whole school, out lucked luck and almost succeeded in bringing the world to ruin. All over her obsession over DesBear.
As far as I'm aware, Yuno Gasai is the only Yandere that has successfully destroyed a world due to an obsession with a love interest. No other yandere comes to mind; now I haven't seen every anime known to man, that's the fun part, there is so much content to immerse ourselves in! So please, if you have a strong burning passion for your yandere share it, unleash your inner yandere and tell me why they deserve the spot. There's nothing I enjoy more than reading other fan theories. It's exciting and beautiful experiencing others interpretations of the different series. We all experience unique perspicacities while watching the same thing, creativity sparks emotion. Share that emotion!