Streets of Rage Mr. X by TenderSman on DeviantArt

Streets of Rage 4 'Mr. X Nightmare' appears on SteamDB teasing possible DLC

Mr. X (Streets of Rage), Videogaming Wiki

Streets Of Rage 4 - Mr. X Nightmare

Sigma Posting on X: Mr. Σ Source: Mr. X Streets of Rage 2 (Genesis) by Sega, Ancient, MNM Software, Shout! Designworks and H.I.C. / X

Streets Of Rage 4 : Mr. X Nightmare Review (PS4) - The Best Side Scrolling Brawler Just Got Even Better - PlayStation Universe

Streets of Rage 4 DLC Mr. X Nightmare, free update announced for 2021 - Polygon

Streets of Rage Remake V5 - Unlockable Character Mr X 3 - Mr X Battle and End of Route

Streets of Rage 4 Mr. X Nightmare DLC adds three new playable characters

Alex Lee - Streets of Rage

Streets of Rage 4: One Year Later..The 'Mr. X' Nightmare Begins. — RGN 99