The game launched for PlayStation 4, Xbox One, and PC in North America and Europe on February 28. The game launched for PS4 and Xbox One in Japan on February 27.
The character pack will include special items and avatar parts. Players can also purchase a character pass that will include the first four DLC character packs. A free simultaneous update will include a new stage. The second character pack will launch this spring, and the third and fourth character packs will debut this summer.

One-Punch Man: A Hero Nobody Knows Game’s Video Previews Suiryu DLC – News – Anime News Network
One Punch Man: A Hero Nobody Knows Will Add Lightning Max as its Second DLC Character – Siliconera
PS4/XBONE【ワンパンマン ヒーローノウバディノウズ】イナズマックスが追加キャラクターとして配信 | ゲームよりどりサブカルみどりパーク