That's definitely something..
"When history witnesses a great change, Razgriz reveals itself... first, as a dark demon. As a demon, it uses its power to rain death upon the land, and then it dies. However, after a period of slumber, Razgriz returns, this time, as a great hero"
Puggz, if its something said ingame, the best way would be reporting that content there when said. In cases where chat identifies someone's wellbeing in jeopardy, Jagex does jump into action fairly quickly.
If its something that was said but wasn't reported, you could email details about it to [email protected] including information such as when it happened so Jagex could try and locate it, but reporting when it happens really is the best way.
If it was something that happened outside of game (social media/skype/discord/twitch), Jagex wouldn't be able to assist and you'd need to contact that platform's support for help.