Summary
Demon Slayerdepicts constant battles between humanity and demons, featuring a variety of swordsmanship techniques, supernatural abilities, and moral dilemmas. AlthoughKibutsujiMuzan and his Upper Moonsare well known for stealing the show with their incredible displays of strength and resilience, there are also demons on the other end of the spectrum whose strength pales in comparison.
Their irrelevance led to the annihilation of the Lower Moon by Muzan, despite being the best of the rest. Although some of these demons are quite formidable and pose a threat at some point in the series, the progression of the characters and stakes has shown that they are small fries in comparison. Without further ado, here are some of the weakest demons inDemon Slayer.

10Kyogai
Former Lower Moon
Kyogaiwas a former member of theTwelve Moon Demons, before being kicked out by Muzan due to his inability to rise through the ranks. As a result, he is no slouch, but he is still one of the weaker demons in the series, and only proved to be a big threat because Tanjiro and his friends were still unrefined in the use of their breathing techniques.
His Blood Demon Art allows him to use Tsuzumi Drums fused to his body to create a desired effect in his mansion, ranging from sending slashes flying to manipulating the space inside the house.

9Slasher
Not Fast Enough For Rengoku
Due to the manner in whichSlasherwas defeated by Rengoku Kyojuro, it is easy for one to think he is at the bottom of the barrel when it comes to demons, but he is quite strong. He appeared during the Mugen Train arc and is known to have had quite a number of human victims.
Slasher is sadistic and has no problems using a young boy as a hostage in order to get into Rengoku’s head. Slasher’s Blood Demon Art gives him quite a speed boost, and makes it really hard for him to be perceived by the human eye, but in the end, he was light workfor the Flame Hashira.

8Spider Demon (Mother)
Subject To Constant Bullying From Rui
Motherwas arguably the weakest member of the Spider Family in terms of actual strength, but she makes up for it with her Blood Demon Art, which allows her to control people and bodies like puppets. The majority of the Demon Slayer Corps sent to Mt. Natagumo fell victim to her puppetry and were used to cut down even more of their allies.
The only reason she joined Rui’s family as his “mother” and put up with his abuse was her fear of being hunted down by Demon Slayers if she stayed alone, which is a big sign of weakness in and of its own.

7Spider Demon (Son)
Not Strong Enough To Defeat The Inexperienced Zenitsu
Sonis one of the few members of the Spider Family that does not take on a humanoid form but instead has a human head on a giant spider body. Son is quite sadistic, as he seems to enjoy whenever Mother is put through the grinder by Rui and Father. He hates humans and enjoys turning them into loyal spider servants with his poison through his Blood Demon Art, over which he can exert his control.
Zenitsu Agatsuma, with very little experience, almost fell victim to him, but he was healed by Shinobu Kocho, who appeared just in the nick of time.

6Spider Demon (Daughter)
Cannot Survive On Her Own
Daughteris evidently the biggest cowardin Rui’s Spider Family,as evidenced by her interactions whenever Rui decides to discipline one of them. She only became a member of the family after Rui rescued her from a group of demon slayers that were about to exorcize her.
She later learned to resent the family and Rui’s idea of how one should operate, and slowly began to think that she might be better off on her own. She can also manipulate threads like Rui and Mother, and this is thought to be as a result of the blood they were made to drink at the point of their induction into the family.

5Susamaru
Defeated By Her Own Tongue
Susamaru, the Temari Demon, was tricked by Muzan into believing she was one of the Twelve Moon Demons who operate under his direct command, and as such, she held him in very high regard. She, along with Yahaba, were tasked with killing Kamado Tanjiro before meeting her demise due to the Curse of Kibutsuji, which destroys any demon who mentions Muzan’s last name.
Her Blood Demon Art was quite formidable, as she was able to go toe-to-toe with Nezuko before the effects of Tamayo’s enchanting blood made her say something she couldn’t take back.

4Yahaba
Deceived Into Thinking He Was A Lower Moon
The Arrow Demon,Yahaba, is one of the two main antagonists of the Asakusa Arc that showed up at Tamayo’s doorstep. Working with Susamaru, he pushed Tanjiro to the limit with hisextremely tedious Blood Demon Art.
Yahaba’s Blood Demon Art was an interesting one, as it applies the concept of vectors, conjuring arrows that can move their target in whatever direction and at whatever speed he wants. He was also deceived by Muzan into thinking he was one of the Twelve Moon Demons, despite actually being one of the weaker ones.

3Swamp Demon
Lost To Tanjiro On His First Mission
During Tanjiro’s first Demon Slayer mission, he encounters theSwamp Demon, which was responsible for the disappearance of young girls in the area. He was the first demon to demonstrate the abilityto split into clonesthat hold different personalities, before Hantengu’s debut.
His Blood Demon Art, Swamp Domain, allows him to manifest a swamp dimension he can use to move around. By creating entrances anywhere he pleases, he can infiltrate anywhere and kidnap people without leaving a trace. He proved to be quite a menace to Tanjiro at the time, but in hindsight, he was a very weak demon.

2Yushiro
Dedicated His Life To The Service Of Tamayo
Yushirowas an extremely frail and fragile human with a terminal illness, and while being a demon has granted him a sturdy and immortal body, he is still weak compared to the majority of the cast, as he has never eaten a human before.
However, he is quite competent at close-quarters combat, and even has a Blood Demon Art that augments those talents. His Blood Demon Art allows him to completely mask or reveal the presence of something through the creation of paper talismans, andby making himself invisible, he can prove to be a real pain in the butt.

1Final Selection Demon
Died Due To His Overconfidence
The demon Tanjiro faced on the mountaintop during the Final Selection arc was an anomaly compared to the demons usually found in the exam, as it had grown abnormally stronger throughout the years due to killing and eating over fifty candidates over the past decade.
Despite growing stronger, theFinal Selection Demonis still one of the weaker demons in the series as a whole,as Tanjiro was able to defeatit with very little experience fighting demons, although it was a tough battle for him.