Slayer across 2 famous tones — mostly through Marshall JCM800 2203, Marshall JCM800 2203 + an overdrive boost, with active humbuckers. Here is where to start, then adapt any of it to the guitar and amp you actually own.
Starting point (averaged): gain 8.5 · bass 6.5 · mid 3 · treble 7.5 · presence 7 (out of 10)