Complex sentence: Leo begins to change the direction of her writing, wanting to focus more on darker themes such as pain and loss, and can no longer write her Amanda Gris novels, whose publishers demand sentimental happy-endings, at least until her contract is up.
Split into simpler sentences: Leo begins to change the direction of her writing, wanting to focus more on darker themes such as pain and loss, and can no longer write her Amanda Gris novels. However, her publishers demand sentimental happy endings, at least until her contract is up.