Drawn with my Sailor 1911s fountain pen (EF nib) on Rhodia dot grid. I love Japan's big 3: Sailor, Platinum, and Pilot. Pilot is my favorite (for the higher ink capacity and slightly soft gold nibs.)
This Sailor is one of my favorites, though, because I like the color and smallish size combined with the firm nib which gives a lot of control when drawing. I'll be coloring this in new software: Clip Studio Paint Pro.