Viscera was introduced to fans as an enforcer of the Ministry of Darkness. He had scary looking outfit and persona which used to frighten his opponents.
#9 Papa Shango
Papa Shango was a voodoo priest who could control Undertaker when he got the urn. His entire purpose was to come in and feud with Undertaker.
#8 Kamala
Kamala was a Ugandan savage who acted as a scary monster which ran over everyone. He started of as a member of Devastation Incorporated.
#7 Doink The Clown
Doink was an evil and sinister clown who used to cheat to win the match. Doink's main goal was to scare kids in the audience.
#6 Boogeyman
The Boogeyman is a frightening figure who instills fear by smashing a clock against his own head and keeping live worms in his mouth.
#5 Kane
Kane was a half brother of the Undertaker who had the supernatural ability to control fire. Kane had been burned and scarred by fire.
#4 Jake The Snake Roberts
Jake was a wrestler who used to come me to the ring with his snake, Damien and often laid him across an opponent after beating them.
#3 Mankind
Mankind was a mentally unstable schizophreniac who came to the ring in a mask and often would sit in the corner, ripping his hair out.
#2 Undertaker
Undertaker was the Deadman, a zombie-like character who came to the ring and put his opponents in caskets at the end of matches.
#1 The fiend (bray wyatt)
The Fiend is an alter ego of Bray Wyatt which is a scary monster who wants to hurt anyone and everyone who gets in his way.