Karl Marx dumped his bastard on Engels and kept writing the workers’ manifesto.
When the housekeeper got pregnant in 1851 he refused to claim the boy, so Engels took the paternity hit while Marx stayed in London drafting class theory.
After that, Engels spent three decades running a Manchester cotton mill, the exact kind of factory Marx called the engine of exploitation, to cover Marx’s rent, debts, and the funerals of 3 of his 6 children who died young.
Before he ever finished Capital, he had already refused regular work for decades, never set foot in a factory himself, and relied on government reports plus Engels’s observations.
In private letters, he ranked people by race and called a rival a “Jewish nigger”.
He died with only volume one published. The unfinished notes became the doctrine later politicians still run on.