is he related to any other family apart from the riddle one?
Yes, Gaunts
Gaunt family
 The Gaunts were once a powerful and influential family, and are the last known descendants of Salazar Slytherin. 
harry potter and the chamber of secrets full book summary The plot follows Harry's second year at Hogwarts School of Witchcraft and Wizardry, during which a series of messages on the walls of the school's corridors warn that the "Chamber of Secrets" has been opened and that the "heir of Slytherin" would kill all pupils who do not come from all-magical families. These threats are found after attacks that leave residents of the school petrified. Throughout the year, Harry and his friends Ron and Hermione investigate the attacks. when was the book published? 2 June 1999 what is the theme of the book? sacrifice, love, friendship, loyalty, prejudice, and racism. does it have any special connection with any other book in this series? Yes, "Chamber of Secrets" has many links with the sixth book of the series, "Harry Potter and the Half-Blood Prince". what is the storyline of that book? The novel explores the past of the boy wizard's nemesis, Lord Voldemort, and his preparations for the final battle against Voldemort alongside his headmaster and mentor Albus Dumbledore what does the headmaster look like? Albus Dumbledore is tall and thin, with silver hair and beard so long that they can be tucked into his belt. He has a very long and crooked nose that looks as if it has been broken at least twice. He is also said to have long and skillful fingers. His eyes are described as being a brilliant, soul-piercing shade of blue, and usually twinkled with kindness and mischief. which skills does he have? Dumbledore is an expert at nonverbal spells and is famous as an alchemist who has worked with Nicolas Flamel, the only known maker of the Philosopher's Stone, and is credited with discovering the twelve uses of dragon's blood. does he have any remarkable possessions? Pensieve, Deluminator, Elder Wand and Phoenix. what is the real name of the boy wizard's nemesis mentioned above? Tom Marvolo Riddle what are his magical strengths? He is known as one of the greatest Legilimens in the world and a highly accomplished Occlumens; he can read minds and shield his own from penetration.
Yes the Gaunt family Yes, the Gaunt family Yes, Gaunt family
Lord Voldemort Lord Voldemort Lord Voldemort
Gaunt family Gaunt family Gaunt family
Most of the exposition of the House of Gaunts background occurs in "Harry Potter and the Half-Blood Prince", through the medium of Dumbledore's Pensieve. The Gaunts were once a powerful and influential family, and are the last known descendants of Salazar Slytherin. However, a vein of mental instability and violence within the family, reinforced through cousin marriages intended to preserve the pureblood line, had reduced them to poverty and squalor, as shown in the Pensieve's "memory" that Harry and Dumbledore witnessed. Like Salazar Slytherin, the Gaunts spoke Parseltongue. At the time of the story, the Gaunts' only material asset is a ramshackle shanty in Little Hangleton, that stood in a thicket in a valley opposite the Riddle House. Like the Riddles, the Gaunts were also unpopular with the local residents, with a reputation for being vulgar and intimidating. Most of the exposition of the House of Gaunts background occurs in "Harry Potter and the Half-Blood Prince", through the medium of Dumbledore's Pensieve.  Most of the exposition of the House of Gaunts background occurs in "Harry Potter and the Half-Blood Prince", through the medium of Dumbledore's Pensieve. The Gaunts were once a powerful and influential family, and are the last known descendants of Salazar Slytherin. 
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Lord Voldemort [SEP] Gaunt family
Most of the exposition of the House of Gaunts background occurs in "Harry Potter and the Half-Blood Prince", through the medium of Dumbledore's Pensieve. The Gaunts were once a powerful and influential family, and are the last known descendants of Salazar Slytherin. However, a vein of mental instability and violence within the family, reinforced through cousin marriages intended to preserve the pureblood line, had reduced them to poverty and squalor, as shown in the Pensieve's "memory" that Harry and Dumbledore witnessed. Like Salazar Slytherin, the Gaunts spoke Parseltongue. At the time of the story, the Gaunts' only material asset is a ramshackle shanty in Little Hangleton, that stood in a thicket in a valley opposite the Riddle House.