In the words of Mythos Pedals:

The Mjolnir is a tweaked version of one of the most sought after overdrives of all time. The latest version of the Mjolnir has a slight reduction in treble and low-mids so that its even more transparent with the gain set low and has a more natural sound with the Tone control at noon. The Gain control has been tweaked for more clean headroom and a sweeter drive sound. For those that havent found the perfect “K style pedal we feel like this take will work for you.