[@Ryougu]
Her transformation to the darkness cloud has no time limit, but she couldn't use her sword attacks or spells. Her offense ability is basically limited to entering someone's lungs and choking them to death, but of course, she could only use it against normal people. She is immune to physical attacks but she can still be harmed by magic. The ability is mostly for surveillance and retreat, as she could just fit herself into the little nooks and crannies. Also easy evasion against physical attacks if she's overwhelmed.

Her death winds could basically insta-kill normal people without any magic defense on them, since it straights up pluck their souls from their body. She doesn't absorb the souls afterwards though. With opponents with magic defense, it's used to wear them down slowly as they have to keep up their defense, wasting their mana in the process. That is, if she doesn't switch it to tornado mode.