Her Constellation, Nyctereutes Minor, changes her playstyle with each activation. Before a certain point, you will need to decide how you want to build Sayu: as a Sub-DPS or as a Healer.

Overall, this is the best set to farm for Sayu no matter what Constellation she has. If you need more healing before C1, then you use Maiden Beloved, but Sayu will be able to take advantage of ...