Four Dark Devas of Destruction

The Four Dark Devas of Destruction (破壊神暗黒四天王 hakai-shin ankoku shiten-ō lit. Four Heavenly Kings of Darkness and Gods of Destruction) are Gundham Tanaka's hamsters consisting of San-D (orange and white), Jum-P (brown and white), Maga-Z (chipped ear), and Cham-P (big and orange).

Appearance
San-D is a fairly average sized hamster with white and orange fur, dark tipped ears, pink hands, feet, and nose. San-D has small black eyes, rosy cheeks, and is usually seen holding a sunflower seed.

Jump-P is also a fairly average sized hamster with white and brown fur, pink hands, and pink feet. Jump-P is usually seen with it's eyes closed, rosy cheeks, and a pink nose. Jump-P is usually seen with a snot bubble and constant z marks flowing from it, indicating it's sleep.

Maga-Z is a fairly average sized hamster with brown and white fur, a chiped ear, pink hands, feet and nose. Maga-Z has slanted black eyes, rosy cheeks, long whiskers and an open mouth.

Cham-P is a large hamster with orange fur, chubby cheeks and pink hands, feet and nose. He has small black eyes, rosy cheeks and a pink rosy mouth.

Prior to The Tragedy
It can be assumed that out of all the animals Gundham had encountered, he enjoyed the presence of the Dark Devas more then any other animal. Thus he brought them with him to Hope's Peak Academy.

It revealed in one of Gundham's free time events that his entire left arm, at least up to the elbow, is completely covered in bandages due to injuries that he received while taking care of or calming down his hamsters.

Island Life of Mutual Killing
The Dark Deva's first appear as Hajime Hinata decides to talk with Gundham at the airport. He appears shocked that Gundham keeps live hamsters inside his scarf, while Nagito Komaeda and Gundham himself don't see the problem.

Throughout the killing game, they apparently often camp out inside the scarf that Gundham always keeps wrapped around his neck, occasionally coming out every now and then.

Chapter 1 - Tropical Despair
The Four Dark Devas of Destruction and Gundham were the ones who found the secret passage to access the Old Lodge's under space where the culprit of Byakuya Togami's executes his action.

Trivia

 * The names all of the hamsters are references to shōnen manga magazines (Sunday, Jump, Magazine and Champion).
 * In an interview with Yoshinori Terasawa, he states that Sonia Nevermind probably adopted the Four Dark Devas of Destruction after Gundham's execution.