Aesop, but not as you remember him
The Victorian children's versions - which we are still reading - bear only the scantest similarity to the originals, I've discovered, since picking up Aesop: The Complete Fables, O. and R. Temple (trans), Penguin, 1998, in the British Museum bookshop. Anyone who writes lots of essays would find it a great resource for colourful introductions: every human quandary is covered, and every emotion.
It can be bleak, e.g.
The Dogs Reconciled with the Wolves
"The wolves said to the dogs: 'Why, when you are so like us in all respects, don't we come to some brotherly understanding? For there is no difference between us in some of our ways of thinking. We live in freedom; you submit and are enslaved by man and endure his blows. You wear collars and watch over their flocks, and when your masters eat, all they throw to you are some bones. But take our words for it, if you hand over the flocks to us we can all club together and gorge our appetites jointly.'
The dogs were sympathetic to this proposal, so the wolves, making their way inside the sheepfold, tore the dogs to pieces.
(Such is the reward that traitors who betray their fatherland deserve.) No 216, p. 163.
But I think my favourite is The Middle-aged Man and His Mistresses
"A middle-aged man who was going grey had two mistresses, one young and the other old. Now she who was advanced in years had a sense of shame at having sexual intercourse with a lover younger than herself. And so she did not fail, each time that he came to her house, to pull out all of his black hairs.
The young mistress, on her part, recoiled from the idea of having an old lover, and so she pulled out his white hairs.
Thus it happened that, plucked in turn by the one and then the old, he became bald.
(That which is ill-matched always gets into difficulties.)" No. 52 (p.42)
I did say they weren't child's play!