S Rank Hero Names
Main Villains By Description/Picture
Saitama's Main Group Of Friends By Clues
Cadres Of The Monster Association
Well Known Villains/Not Main
100

S Rank #1 

Blast

100

Universal Destroyer. Wears armor that suppresses his "boundless" power.

Lord Boros

100

His Protege

Genos

100

A black member that has an inappropriate full name

Black Sperm

100

A Sea Monster

Deep Sea King

200

S Rank #17

Puri-Puri Prisoner

200

Leader Of The Monster Association. aka The Monster King

Monster King Orochi

200

Some sort of weather we are having?

Fubuki/Hellish Blizzard

200

A Large insect that was defeated by Saitama

Elder Centipede

200

A Titan

Beefcake

300

S Rank #5

Child Emperor

300

Student Of Bang who rebelled against his master. Later declares himself a monster.

Garou

300

An S rank hero that is not what he seems

King

300

An extremely strong martial artist that undertook the monsterisation process to become even stronger. He defeated Suiryu and was subsequently destroyed by Saitama

Gouketsu

300

A Crab

Crablante

400

S Rank #8

Zombieman

400

Ninja That Was Contracted by Mr. Monier to defend him against a group known as The Paradisers

Speed O Sound Sonic

400

An old martial artist

Bang

400

A monster that took on the name of a japanize beamed cat meowing

Nyan

400

A Piccolo 

Vaccine Man

500

S Rank #10

Pig God

500

First Villain That Gets Defeated By A Slap

Mosquito Girl

500

An old martial artist's older brother

Bomb

500

Co-Leader of the Monster Association

Psykos

500

A Last Ditch Monster From The House Of Evolution

Carnage Kabuto