(1) Because in the first Harry Potter and the Sorcerer's Stone, Malfoy wanted to make friends with Harry, but Harry refused. Malfoy was very angry, so he later planned to get back at Harry, which was a bit childish. In addition, Slytherin and Gryffindor are the two most incompatible colleges.

(2) Malfoy's favorite is not mentioned in books or movies, but in the last chapter of the seventh Harry Potter and the Deathly Hallows, Malfoy is married to astoria greengrass, who is greengrass's little sister and has a son, Scorpius Malfoy.

(3) Malfoy is the malfoy family's only son, pure blood, and a death eater (forced to participate).

(4) Malfoy's father lucius malfoy, pure blood, death eaters, is also a senior official of the Ministry of Magic.