Technically not the greatest villain of the series, Shinobu Sensui was definitely among the best.
With him being a former Spirit Detective was a very impressive twist.
Unlike Yusuke Urameshi, he never struggled in his early days from what it seemed.
But after a decade of hiding in the shadows, he decides to end all of mankind with a portal leading to Demon World.
After the Dark Tournament, it was strange to see Yusuke Urameshi be outmatched.
Though it always seemed to be manageable, if he played his cards right.
Turns out his fall from grace resulted in him having multiple personalities.
With his true self being in the S Class of power, and he had this fancy sacred energy.
Where he easily killed Yusuke Urameshi, ironically triggering a rebirth of him as a demon.
He managed to get everyone to fall for his traps.
I really enjoyed watching him fight Hiei, Kurama, and Kuwabara.
And him and Yusuke have a pretty decent fight.
Until Raizen took over Yusuke’s body and slaughtered him.
After he dies, he spends eternity in a dimension with his BFF. Sounds boring…