So in other words, we need to borrow someone else's body.

Correct.

A highly virtuous Daluo Jinxian would be one thing... TN: One of the highest "levels" of hermit

But if a lowly shikaisen's yuanshen is without a body for too long, it'll start to change.

Just look at Tojiko.

And vengeful spirits aside...

Depending on your temperament, you might become some other sort of youkai. Fascinating, don't you think?

Oh, by the way...

The Myouren Temple cemetery is least defended around noon.