N-Daguva-Zeba: He was ancient enemy to Kuuga and arch-enemy to Kuuga, he want to make this world fall into darkness. He send Gurongi to kill Kuuga and love to kill people for fun. He also work with Shao Kahn.

Shao Kahn: He was the one who make Mortal Kombat Tournament and the one who hate Kuuga, he is chosen warrior to kill opponent and chosen them to become champion. He also hate someone ruin his plan.

Kano: He was rogue mercenary and mentor to Arata Matoi before he become villain, he become leader of Black Dragon and kill innocent people for fun. 

Kabal: He was once servant work for Shang Tsung and he leave his boss before join Black Dragon, he use super speed to catch up his enemy and he is vert tricky.

Mileena: She was clone daughter made by Shang Tsung and she hunt Kuuga, she kiss Kuuga 15th time and she flirt with Kuuga by force him to join her and become her husband. She also hate Shinobi who is very annoy to her. 

Bi-Lin (Noob Saibot): He was previous Subzero and he the one who kill Scorpion's family, he was kill by Goldar and become Noob Saibot to kill Kuuga and Subzero aka Shiro Lin. 

Goldar: He was once enemy to Power Ranger before he was revive by Shang Tsung, he join Shang Tsung and rival to Kuuga. He also obey his master's order.

Shang Tsung: He was arch-enemy to Liu Kang and Kuuga, he stole people's soul and become god to rule everything. He was seal back by Raiden and he was return back from death. He is very manipulative man. 

Quan Chi: He was the one who revive Kenji back from death and turn him into Specter. He also hate Kuuga for ruin his plan and he work with Shang Tsung. He bring everyone back from death by turn them into evil.