|＼　　 　 　 　 　 ／|　　　
　 　 　 　 |＼＼　　 　 　 ／／|　　　　 　
　　　　 　 : 　,>　｀´￣｀´　<　 ′　　 　
 　　　　 　 Ｖ　 　 　 　 　 　 Ｖ　　　　
 　　　　 　i{ 　o　 　　 o   　 }i　　　　
　　　　 　 八　 　､_,､_, 　 　 八　　　その願いは君にとって、魂を差し出すに足る物かい？
  　 　 　 /　个 . ＿　 ＿ . 个 ',　　　　　
　　　＿/ 　  l 　 ,'　　　 '.　 l 　 ',＿_ 

The dessert witch, with a tenacious nature. She desires everything. She will never give up. Though she is capable of creating infinite amounts of any dessert she desires, she is unable to make the cheese that she loves most. One could easily catch her off-guard with a piece of cheese.  

Speculation

Charlotte might have been a cancer patient. Patients undergoing chemotherapy are unable to eat certain foods such as cheese. This would explain her hospital-based labyrinth theme and the location of her grief seed. Kyubey is likely to target terminally ill girls. In that case, her caterpillar-like second form would represent unlimited reproduction of cancer cells.

- Puella-Magi Wikia

I haven’t read the manga spin-offs of MSMM yet but I’d like to learn more about Charlotte’s human form if they ever decide to reveal it.

I’m also curious about who Walpurgis Night was before because I quite liked the “mash-up of many witches” and “Homura” theories both.

I’m not hoping for another season right now but I’d sure love to see more spin-offs about many things that could get more details in the series.