4 ideas
His mistress Champa plays on their longing for a child by urging them to vow a temple to the village goddess. Mangaraj lends them the money on a mortgage bond he manipulates, then takes the land through the courts; Saria dies and Bhagia goes mad, and Mangaraj is himself later stripped of everything by his own lawyer and associates.
The narrator extols the villain's piety, prudence and wealth-building as virtues, which lets him describe each technique of extortion in plain, admiring detail. Because the reader supplies the moral judgment the narrator withholds, the satire gets past the respectability of the powerful. The same phrasing that would flatter the powerful man ends up indicting him.
Under the new regime of written deeds, stamp paper and district courts, land passes to whoever controls documents and can afford litigation, whatever the actual history of use or ownership. Illiterate cultivators and artisans cannot contest a forged or manipulated bond. The legal system therefore works as an efficient machine for dispossessing them rather than as a protection.
The moneylender does not wait for the poor to fall into need. He creates the borrowing occasion by attaching it to their deepest desire, here a child through a religious vow. Debt taken on for hope rather than survival feels voluntary and pious, so the borrower walks into collateralizing their only asset without suspicion.