Story ideas and more.

Characters

This is Characters that would make terrifying Yanderes
(in my opinion),whether it be power or an army it doesn't matter beside a yandere can handle the job on their own if they have to.

10. Floofty from Bugsnax's, Floofty without being a yandere is already feared by everyone else, they're also smart but are rivals with there brother snorpy. Now if they were yandere they would train a bugsnax to watch over you, attack anyone or even kill them, and to protect themselves. Floofty who cut their own leg off and tried to cut their head off is probably just going to use the person getting close to you as a experiment subject. Floofty would probably use melee weapons like knifes or a carved spear for longer range. However once everyone picks up about Floofty they're probably get lock away since it's them and the bugsnax against 11 others.

9.Sundrop and Moondrop from Security breach,Sundrop who is already taller than a human,is made to chase after children, flexible,can climb through vents, probably has high endurance and is the least expected to become a yandere is terrible combo if you want to escape from him. Moon however can use the pulley, stealth, highly aggressive if someone isn't asleep and good hearing he could be suspected to be a yandere since his aggressive but since he has sun it's a 50/50 chance. Not only that but he has a whole daycare so he's reputation would be high making him seem like he's not a yandere unless Moon messes that up.

8.Blixer from Just shapes and Beats, Reason why I'm putting him so high is because of his aggressive toward others (it'll make it obvious) and him taking over paradise however he can counter this with the pink corruption,his army,the tree of life and his final form. But even with all that power the four heros,Heli and Captain can defeat him with one part of the tree of life. Even after he's defeated he joins the rest and becomes a DJ.

7. Peter the pumpkin from Andy's apple farm,The one who trapped everyone in the computer with the help of Andy. Now much isn't known about him but from what I can tell he plays god in the computer messing with the characters, setting and even the dialogue. However they seems to be a way to get rid of him but it's kinda unknown at the time being,still the games he played with Andy and controlled him makes him terrifying Yandere.

6. Come on now most know you can't have a yandere list if you don't mention the one who started it all (probably),Ayano from yandere simulator. Even though she has no powers, she's capable doing lots of damage with just her hands. She basically knows what she's doing and will keep anyone away from her senpai, whether it be stabbing, burning,electrocution, strangling, drowning, poisoning,$*i*id3,manipulating, falling,crushed and more.

5. Now this one is difficult because of the multiple characters that could be here but I'm going to put the jester trio here.(Marx, Dimentio and Jevil) All of them are capable of destroying worlds,Marx is a frickin god, Dimentio can destroy worlds and make new ones,Jevil is kinda f*cked in the head but is powerful. But that's just on their own.

4. Now this one is more easier than 5, Snatcher,Moonjumper and Vanessa from a hat in time.To start off Snatcher rules over a forest with the help of his minions. He can make fires,take souls,strike down lighting, and can summon blue potions, Vanessa was kinda a yandere to being with but I'll go on. Vanessa can form ice,snow and control a headless statue outside of the manor. She also freezes anyone who comes in her manor with permission. Finally Moonjumper who is stuck in a place called the horizon. He can use red strings like puppeteer on victims and also uses them to control people and can form contracts like Snatcher. If all three were to team up against a person, two words:

You're pecked

3. Now I was trying to decide who would be more powerful so I'm going to say Monokuma from Danganronpa. Monokuma the headmaster basically is the one who can execute students if they break the rules or got caught with a murder like "Junko" when she got impaled by spears for violence against headmaster or Leon who was executed for trying to defend himself from Sayaka.

2. Again no big surprise I would say Pal from the Mitchell's vs the machines. One, she managed to overthrow humans in at least a day except the Mitchell's,can hack emails if wanted meaning she can track you down if she wanted, has a entire robot army that can only be defeated by killing the queen or using Mochi then hitting them,made more advanced robots and made a prison no one could get out of except the Mitchell's. Overall she would be a terrifying Yandere especially if this was going on.

Honorable mentions.

Flowey from Undertale

He became a god in the end, and I can't forget about Photoshop flowey. He can just reset over and over again and could kill anyone except Frisk who's determination is strong.

Danganronpa

Now this one would just become it's own chapter if I were to list the characters but since anyone is capable of murder here,plus their ultimates also help depending on the situation.

1. Is the all mighty Bill from gravity falls. I've seen what he has done from invading minds to growing more limbs and even killing time baby. He can manipulate reality like he did to Mable and strike up a deal. All it takes is a snap of his fingers and you could be teleported to him or he could cause the end of the universe itself,who knows.

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That's the characters that would make terrifying Yanderes,based from opinions goodbye!