FAUST's Links
Faust is one of the very few people that knows of Law's past. While they were very close friends then, the two is now reserved towards each other - mostly out of tradition. Nowadays they only interact when Law asks Faust for a favour... mostly to vanquish annoying powerful men that has ever remotely bothered Law.
Law knows Faust from the past, in her beast-slaying heydays. Now that she's retired, she'd rather not associate with anything related to her former job - though Faust is an exception. The two are friendly, but do not talk to each other - unless Law asks Faust for a favour.