img2img turned a mace doodle into a nice illustration

Tried again with another doodle, this time using a straighter handle. If you start with a straight handle, it'll keep the handle straight. https://i.imgur.com/SjweUbH.png

I'd imagine it's because the original doodle is also a bit out of alignment. You could try warping it in an image editor, I suppose. Or rotating the handle and re-diffusing it.

Here's an example of the first method, warping the handle into shape: https://i.imgur.com/icqsz2e.png

Here's an example of the second, rotating the handle and rediffusing: https://i.imgur.com/VmyDMbI.png

A third way would be to just make sure you're using straight shapes in your original doodle, or to pick a final image with a better handle. Some of the maces I generated were definitely straighter.

In the end, it's about what you're satisfied with. Let me know if you find a better way!

Prompt was "fantasy flanged mace with runes d&d magic item artefact, ruby, artstation digital art". If I remember correctly, I used img2img with a denoising strength of 0.35, picked my favourite image, and then ran it through a second time. I definitely ran it twice with low-ish denoising strength settings.