It's a prequel to Bone, but it's not comedic. I hadn't been expecting anything like this at all. It's a completely different mode of storytelling that happens to be set in the same fictional universe. It's a fairy tale. That's true of both the script (which appears to be borrowing from the Lambton Worm legend) and the artwork (the magical Charles Vess).
I'm reminded of the difference between the Star Wars original and prequel trilogies, except far more so. (Like the Star Wars prequel trilogies, this comics series lacks a down-to-earth everyman figure, instead starring princesses, mentors and other people who say things like "do not patronise me, my sister". They're also both tragedies, setting up the dark rise of magical villains while the surviving prequel hero will go off to live in the middle of nowhere under the name of Ben and tell lies to the next generation's hero on a farm.)
To be honest, I didn't think it was that good. It's okay, but I missed the light touch of Smith's humour. It's all very formal and "my lady", with no one to just relax and be themselves. Rose's talking dogs fill that role, theoretically, but they're just dogs. We know they don't matter.
Instead of trying to make you laugh, it's basically a tragedy... but I'm not sure it quite lives up to what we'd been led to expect by Bone. It's not clear from this series why elderly Rose will be so hostile to the red dragon, for starters. The red dragon tells Rose some shocking things, but he's always on the money and it's Rose who lets down the dragon, not the other way around. Above all, this is a fairy tale and the iron law of fairy tales is "follow the rules". If a passing sparrow tells you to lick your elbows three times before you open your eyes tomorrow morning, then you'd damn well better lick those elbows or you know you'll be sorry. Rose keeps doing the wrong thing.
Everyone seems to think that this book works best if you've already read Bone, but personally I'm tempted to say that you'd be better off reading this with no expectations. If you've no idea how it'll all end, you'll be in for a shock.
It's... interesting. I don't think it really worked for me, but I was impressed to find something so different. It's cool to see Charles Vess's take on Smith's creations, like the red dragon (identical) and the rat creatures (more sinister). Smith's art has stronger character acting, but you could hardly pick a better artist than Vess to draw a fairy tale. I'd recommend forgetting that Bone exists while reading this. The comparisons and tonal differences don't help it, while the story's strongest (i.e. darkest and most shocking) elements are from the old English legend it's semi-adapting.