Yeats' Crazy Jane avatar appears in poems ranging from the late 1920s until his very last collected work. She is literally a descent. Naughty (what's the difference between a solid man and a coxcomb?), sexy and maybe mad; and he puts her through it.
She can says things he can't say.
Crazy Jane talks with the Bishop
I met the Bishop on the road
And much said he and I.
'Those breasts are flat and fallen now,
Those veins must soon be dry;
Live in a heavenly mansion,
Not in some foul sty.'
'Fair and foul are near of kin,
And fair needs foul,' I cried.
'My friends are gone, but that's a truth
Nor grave nor bed denied,
Learned in bodily lowliness
And in the heart's pride.
'A woman can be proud and stiff
When on love intent;
But Love has pitched his mansion in
The place of excrement;
For nothing can be sole or whole
That has not been rent.'