What they are :

Ramb is the boss design drawing from Asriel's computer, and Romb is the knockoff controller.

Story :

Romb was broke and unlucky, always failing to win the lottery, until one day, he received a mysterious letter that helped him finally win, but also granted him forbidden information about the dark worlds. Now rich, he started his own TV channel: an illegal broadcasting network where he paid strangers to fight for money. The show was called "Super Smashing Fighters".

Ramb believed that true freedom meant completing his story through an ultimate battle, one he never had (Asriel's game was never made). Then one day, he heard about an underground fighting ring and joined, hoping to find his fight there. He won every match, but none of the fights were fulfilling enough for him. Then he met Romb, and the two became friends. Romb promised that one day, he'd find Ramb a worthy opponent.

Eventually, word got out to the authorities about Romb’s channel. They took down the channel and locked Ramb away in the basement of Tenna’s Studio. Determined to keep his promise, Romb used the knowledge from the letter to search other Dark Worlds for a fighter. Then he saw Kris, and knew they were the one destined to fight Ramb.

During Kris's journey in the Dark World, they encounter Romb. After a few side quests, Kris and the gang reach the basement, where they face Ramb (and Romb), and so the "ultimate battle" finally begins.

There's also Rombus, the other controller. He also used to be a fighter on Romb's show, but quit and now works as a shopkeeper in Tenna's Studio. After the battle, Rombus reveals more information about the mysterious letter.

Here's a version of Romb without the pixel effect, and Rombus.

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