The upcoming Mappa's anime Chainsaw Man needs a fitting first opening, and the only acceptable song for this purpose is Devil in Your Heart from "SiM".

This song describes many aspects of the Manga's story, and it's metalcore style fits incredibly with the overall aesthetics of Tatsuki Fujimoto's works.

It is important to note that, the Fan community also embraces this idea. This Fanmade Opening with more than 5 Million views can tell that. 

The musical group "SiM" already worked with Mappa studio in a preview project: Attack on Titan. They have made a new song for the show, named The Rumbling, wich was very well received by the fans. Because of this previous work, it is not impossible to make them work together again. 

To make this Fan community dream happen, we need to make pressure in Mappa's social media, and ask them to work with SiM one more time to make Devil in Your Heart the first opening of Chainsaw Man.