Marriage between the great families was a common practice. There were various reasons for these arrangements—to foster peace and avoid conflicts between powerful forces, to build connections, and to stand strong against other influential houses.
Renard's betrothal was exactly such a case.
House Grace, one of the eight great houses, was located in the northern part of the Astralis Continent, right beside the borders of House Grim. Unlike all the other houses, House Grace didn't specialize in combat. Instead, they were master healers and spirit contractors.
Yes, spirits. Like House Grim, they were masters who made contracts—except they didn't bond with beasts. Instead, they formed pacts with spirits from the Spirit Realm using their divine power.
Spirits were beings from another realm, which meant the power they could exert in Astralis was limited. This placed House Grace on the lower side of the eight great houses in terms of strength, unlike the Grims.