Muggles' Guide to Harry Potter/Characters/Marvolo Gaunt

Overview
Marvolo Gaunt, patriarch of the remnants of the once-proud House of Gaunt, is a descendant of Salazar Slytherin, and grandfather of Lord Voldemort.

Chamber of Secrets
In Tom's memory, as replayed by the diary, the sixteen year old Tom Marvolo Riddle reveals to Professor Dippet (who was headmaster at the time) that he was named Tom after his father and Marvolo after his grandfather. (Tom did not write his full name in the diary, apparently only marking it with "T. M. Riddle".)

Half-Blood Prince
Marvolo is first seen when appears to restrain his son Morfin, who has just assaulted a Ministry wizard, Bob Ogden. He is described as being oddly proportioned, with wide shoulders and overlong arms.

When Ogden explains that Morfin is being summoned to a hearing for having Jinxed a Muggle, Marvolo seems unconcerned; after all, it was only a Muggle, so no harm done. When told that Morfin has broken Wizarding law, he shows Ogden the ancestral ring of the Peverells, and the locket of Salazar Slytherin, as proof he can trace his ancestry back to the earliest and purest Wizarding families. Ogden's protests that blood does not outweigh law fall on deaf ears. Meanwhile, Marvolo is bullying his daughter Merope, becoming enraged when it appears she fancies a Muggle, Tom Riddle, the same one Morfin Jinxed. Marvolo attacks Merope; Ogden defends her, but has to flee Morfin.

When the Ministry return to arrest Morfin, Marvolo resists, and is arrested, tried, and sentenced to six months in Azkaban. When he returns from prison, he finds his daughter has run off with the Muggle; he never again speaks her name and never forgives her, and dies before Morfin gets out of prison.

Weaknesses
Marvolo is menacing to strangers, and never wants to associate with others in his area. He is even cruel to his family, particularly his daughter Merope, whom he berates because of her comparatively weak magical talent. He barely even talks to his son Morfin; the thing he values the most, above his children, are the family heirlooms. He is full of immense pride for his heritage as a descendant of Salazar Slytherin, and because of this, holds himself in high regard, even though he and his family are impoverished.

Relationships with Other Characters
Marvolo abuses his daughter, Merope, for not doing proper magic, when it was clearly his own fault for not helping Merope control her magic or presumably refusing to let her even attend a wizarding school such as Hogwarts. He always demands that Merope would take care of him. This is proven that after he returned home from Azkaban, he expected his daughter would await his return and have a hot meal ready on the table. Instead, the house was very dusty and Merope had a letter of farewell revealing what she did. Marvolo never forgave Merope for her actions and died shortly after, since Marvolo never learned how to take care of himself.

Both Marvolo and Morfin share an ideal of hating and hurting Muggles for the sake of it. Unfortunately, this ideal caused them to land themselves in Azkaban. They also abuse Merope when they found out she was in love with the Muggle, Tom Riddle Senior.

Greater Picture
The Gaunt family represent the worst aspects of Wizard Pride and pure-blood mania. Although descended from Salazar Slytherin, generations of in-breeding, bigotry, laziness and feelings of superiority have ruined the Slytherin line. Their wealth had been squandered generations ago and the Gaunts now live in isolated squalor, hating everyone who are not pure-blood wizards. Marvolo considers himself a wizarding aristocrat, but in fact is a violent, bad tempered, ignorant tramp. Marvolo is a useless man with no ambitions, no respect for others (including his own children) and no social consciousness.

The folly of both pure-blood pride and "Wizards First" arrogance is a recurring theme throughout the series. The Gaunts and their last descendant, Voldemort, represent the dangers (and foolishness) of racial superiority, intolerance and aristocratic entitlement that is still widespread in the Real World.