(Contains Heavy Spoilers)
Adults:
Duke Matthew Bigcoc - Adam's Father
Rosalind Stewart - Matthew's 1st Wife
Elizabeth Bigcoc (Booty) - Matthew's 2nd Wife, Adam's biological mother
Isabella Heart - Matthew's 3rd Wife
Children:
1) Serena Stewart- Rosalind's 1st child
2) Luna Stewart- Rosalind's 2nd child
3) Ulena Stewart- Rosalind's 3rd child
Pam Stewart- Rosalind's 1st adopted child
4) Siliana Stewart- Rosalind's 2nd adopted child
5) Adam Bigcoc- Elizabeth's 1st child
6) Emma Bigcoc- Elizabeth's 2nd Child
Raphalia Heart - Isabella's 1st child
7) Sadina Heart- Isabella's 2nd child
Pomeria Heart - Isabella's 1st adopted child
Suna Heart - Isabella's 2nd adopted child
8) Ophelia Heart- Isabella's 3rd adopted child
In terms of age (from the eldest to the youngest): Raphalia, Pomeria, Serena, Luna, Adam, Siliana, Suna, Sadina, Emma, Ulena, Pam, Ophelia.
As of chapter 110, only the numbered children are recognized by Matthew, and therefore considered a part of the main Bigcoc mansion. Other children have little to do with Matthew, and thus have hidden identities.
Other relations:
Duke Hormon Al Stewart - Rosalind's father
Duchess Lippes Stewart - Rosalind's mother
Baron Kurvee Booty - Elizabeth's father
Baroness Finessia Booty- Elizabeth's mother
Rodeo Booty- Elizabeth's older brother
Sheona Booty - Elizabeth's younger sister
Tempo Booty - Elizabeth's younger brother
Isabella's family details will be updated in the future.
Note: Some terms like half sister and cousin, step sister and adopted sister have been used interchangeably (done on purpose).