Akaza is a major antagonist in Demon Slayer: Kimetsu no Yaiba. He is a demon serving directly under Muzan Kibutsuji, and currently holds the position of Upper Rank Three of the Twelve Kizuki. Akaza is a strong, stubborn and battle-crazed Social Darwinist who enjoys fighting, especially against strong Demon Slayers. He purposefully drew out fights so as to savor every moment of it, also complimenting his opponents when they unleash strong techniques or land blows on him. He loves rengoku 

Flirty, combative, loyal, strong, and violent 

Kokushibo is a major supporting antagonist of Demon Slayer: Kimetsu no Yaiba. He is a demon affiliated with the Twelve Kizuki, holding the highest position, Upper Rank One. Kokushibo is reserved, silent, and aloof, maintaining an aura of unnerving tranquility and mystery that compliments his position as Upper Rank One. He rarely speaks; when he does, he talks in a slow and emphatic manner that gives more gravitas and authority to his words. He is an adamant rule-follower, punctual, respectful 

Quiet, intimidating, powerful, majestic, envious

Kyojuro Rengoku (煉れん獄ごく 杏きょう寿じゅ郎ろう, Rengoku Kyōjurō?) was a major supporting character of Demon slayer
Kyojuro was greatly enthusiastic in regard to his duties as a Hashira, and often came across as cheerfully eccentric. He was amiable, pure of heart, and boasted extraordinary technique and swordsmanship stemming from strict practice friends with Uzui Tengen

Loud, and extroverted but always positive.  

 Domais a major supporting antagonist of Demon Slayer He is a demon affiliated with the Twelve Kizuki, holding the second highest position, Upper Rank Two Doma is outwardly friendly, possessing an approachable and charismatic air and described to talk and act in a calm and carefree manner by Kanae Kocho. However, it is soon revealed that Doma has psychopathic tendencies, adopting sick beliefs and habits like ruthlessly and happily murdering and devouring his cult's followers. He’s openly pervy 