Numbers are the honest way in with Arthur Inverse. Dual Class 3 alone runs past twenty-seven hours and has drawn hundreds of listener ratings, which places the sequence squarely in the LitRPG corner of fantasy, where sheer scale is part of the appeal rather than a side effect of it.
The Dual Class books straddle fantasy and science fiction, the hybrid ground that progression fiction has made its own: game systems, levelling, stakes that escalate with each instalment. This is writing for listeners who want to move into a world for weeks rather than visit it for an afternoon.