Lily Evans' Marauder Twin Sister
Scarlet and Lily Evans are two very different people.
Lily is responsible, coordinated, organised, a prefect, she always does her homework, she thinks Quidditch is a waste of time, best friends with Severus Snape and hates the Marauders.
Scarlet is childish, clumsy, messy, a prankster, never does homework, is a Beater (alongside Sirius) on the Gryffindor Quidditch team, hates Snivellus and is best friends with the Marauders.
Its a miracle these twin sisters get on!