A1 - RON: Scabbers! My pet rat is in C2 in a row filled with animagi and the werewolf Marauder, and no one in my diagonal has killed a member of the Order of the Phoenix.
Therefore Peter Pettigrew is in C2
C2 - Peter Pettigrew: The alliterative named animagus is in C4, no one who has written a book is in this quiz, and C5 died in the battle of Hogwarts.
(Ron) Everyone except Lupin (werewolf member of the marauders) in C is an Animagi – the animagi in the series are James, Sirius, Professor McGonagall and Rita Skeeter. (Peter) Rita Skeeter has written a book so is not in the quiz. This leaves row C being filled by Peter Pettigrew, Sirius Black, James Potter, Remus Lupin and Professor McGonagall. The only animagi with an alliterative name is Minerva McGonagall so she is in C4. The only remaining person in row C who died in the battle of Hogwarts is Remus Lupin, so he is in C5.
C4 – Minerva McGonagall: No deatheaters are adjacent to a Hogwarts professor, and Molly Weasley is in the same row as the woman who tried to kill her daughter.
C5 – Remus Lupin: My wife's mother and her mother's two sisters are in my column and Snape isn't in this quiz.
(Remus) Remus's wife's mother is Andromeda Tonks, and Andromeda's sisters are Narcissa Malfoy and Bellatrix Lestrange. They must all be in column 5. (Minerva) Molly Weasley will be in the same row as Bellatrix Lestrange. Bellatrix is a death eater, so cannot be in B5 or D5 (she must be either A5 or E5). (Ron) E5 is in Ron's diagonal, and Bellatrix killed Sirius (a member of the Order of the Phoenix, so Bellatrix cannot be there. Therefore she must be in A5.
A5 – Bellatrix Lestrange: McGonagall is adjacent to 3 members of the Order of the Phoenix, and Ron is an a column with two people who have the same four legged patronus.
The only 2 pairs of people in the Harry Potter Series with the same 4 legged patronus are Harry+James and Lily+Snape (Fred and George have the same patronus but it is a magpie so not four legged). (Remus) Snape is not in the quiz. The only pair left is James and Harry. (Ron) We know James must be in row C, (Bellatrix) in column 1 so James will be in C1. This means Sirius will be in C3, and Harry will be somewhere in column 1.
C1 – James Potter: Bellatrix is adjacent to two house elves who have been inside Grimauld Place, and there's a Weasley in the diagonal with Ron
C3 – Sirius Black: Andromeda is not adjacent to any of her blood relatives, and Harry shares a diagonal with Dobby and a person Dobby saved from Malfoy Manor
(Remus) We know Andromeda has to be in column 5, (Sirius) and cannot be in B5 because that is adjacent to her sister Bellatrix. This means Andromeda is either in D5 or E5. For either of those, Narcissa cannot be in the other one because she is Andromeda's sister. This means Narcissa must be in B5.
(James) The two elves who have been inside Grimauld Place are Dobby and Kreacher. This means Dobby and Kreacher are in A4 and B4.
(Bellatrix) We know Harry must be in column 1. (Sirius) He is in a diagonal with either A4 or B4 which means Harry is either in D1 or E1.
B5 – Narcissa Malfoy: Row E are all members of Dumbledore's Army, and Andromeda shares a row with her grandson's godfather
(Narcissa) Andromeda cannot be in E5, so she must be in D5. Andromeda's grandson is Teddy Lupin, whose Godfather is Harry Potter. So Harry must be in row D with Andromeda. We know Harry must be in column 1, so Harry is in D1.
D5 – Andromeda Tonks: Harry and Ron are each adjacent to both of their parents, and Lupin is adjacent to 2 other Hogwarts Professors
D1 – Harry Potter: There are 5 Weasleys in this quiz, and the youngest of the 5 is not in a diagonal with anyone who was born with the name Black
