Sometimes protagonists aren't the only ones stealing the show; antagonists shine just as bright.
In many anime series, we encounter formidable antagonists, characters crafted with brilliance. Some are terrifyingly evil, earning hate from both characters and fans. Yet, sometimes, these villains are oddly endearing. Of course, audiences should never forget their true nature—they're killing machines.
10. Petelgeuse Romanee (Re:Zero - Starting Life In Another World)
Betelgeuse serves as an archbishop within the Witch Cult, representing one of the Seven Deadly Sins—sloth. He's fearsome, powerful, with peculiar mannerisms. However, over time, his terror becomes somewhat comical, endearing him to viewers.

Nevertheless, Petelgeuse remains fiercely loyal to the Sloth Witch and refrains from causing harm. Each of his appearances is akin to a piece of art. Particularly memorable is his anxious nail-biting, contorting his body 180 degrees, accompanied by a sinister grin.
9. Tomoe (Tsuki Ga Michibiku Isekai Douchuu)
Tomoe finds herself bound by a contract with Makoto in Tsuki Ga Michibiku. Despite being a dragon, she acknowledges Makoto's superior strength and willingly becomes his servant. Embracing her new role, Tomoe enjoys exploring Makoto's memories, watching anime, movies, and diving into novels.

Once revered and feared as a dragon, Tomoe's solitude was interrupted when the protagonist discovered her. Previously relegated to a desolate mountain, chosen as a sacrificial site by locals, she now serves a new purpose.
8. Mio (Tsuki Ga Michibiku Isekai Douchuu)
Mio stands as another loyal servant of Makoto. She roams across dimensions in search of sustenance, always embodying a daring villain. In her past, Mio reveled in destruction, willing to kill and consume any creature to satiate her hunger. Her power and cunning nature inspire dread in many.

No matter how much Mio eats when hunger strikes, she relentlessly seeks something new and delicious. Consumed by her love for Makoto, she becomes his faithful servant, fighting alongside him shoulder to shoulder. Henceforth, Mio predominantly assumes the role of a formidable guardian angel, ready to eviscerate anyone who dares harm her beloved.
7. Hanzo Urushihara (The Devil Is A Part-Timer!)
Hanzo, once a fallen angel serving Lucifer and one of the generals of the Demon King, Sadao Maou. He was ruthless and cruel in The Devil Is A Part-Timer! When Hanzo began to defeat Lucifer, he realized redemption in betraying the Demon King. In the battle, Lucifer lost and (after reconciling with Sadao), he set off to return home.

Lucifer (Hanzo's real name) became a brilliant programmer and embarked on his own hikikomori lifestyle. He loves the lifestyle of not moving and doing anything else. Without a doubt, Lucifer is one of the laziest characters in isekai anime, but he's content with Sadao bringing food every day.
6. Shiro Ashiya (The Devil Is A Part-Timer!)
As one of the generals of the Demon King, Shiro leads his army to vanquish enemies. He is extremely intelligent and can devise the best strategies beneficial to both sides.

Shiro Ashiya is one of Sadao's most loyal generals. Upon discovering he had arrived in Japan, he began searching for books to help him return and regain his powers. Primarily, he does household chores like laundry and cooking.