You are not allowed to use this character/design anywhere in any way, shape, or form without express written permission from me (unless you're making fanart).
I asked for a steampunk-themed pony and Twii came up with this amazing design. I would claim her for myself but I think sharing her with Twii would be a lot more fun. Originally it was created for someone, but seeing as how she was never put to use (likely for the same reason I'm afraid to take her for myself -- so many details, hard to draw XD), Twii and I talked and decided that she'd take ownership back and call it her's instead. I only claim partial ownership because it was my idea and I helped with the overall design.