Can You Play Hero Rising Online? No—Cancelled Mobile MMO by Nexon (~2014)

No. Hero Rising Online was a mobile MMO in development by Nexon (announced ~2014) but was cancelled before release. No servers, website, or playable builds exist.

If you're looking for similar superhero MMOs, try:

• DC Universe Online (PS3/PS4/PC/Switch)
• Champions Online (PC)
• City of Heroes (private servers: Homecoming, Rebirth)
• Marvel Heroes Omega (shut down 2017; private servers in development)