At its core, the is a custom raster brush included in the Kyle T. Webster’s Megapack (now included for free with any Adobe Photoshop subscription). The name "Nikko" likely draws inspiration from Nikko, Japan—a city known for its ornate, textured nature—while "Rull" evokes the idea of a roller or a rule.
Nikko Rull is greatest brush in procreate. I will fight anyone who says otherwise :) nikko rull brush photoshop