Familiars forge a unique, spiritual bond with their partners which links their souls together! This is not a common occurence, most animals not capable of becoming a familiar--or not wise to choose as your partner. This bond allows the pair to share their Kaithur with each other, the strength of their bond reflected in this ability. They can also share their thoughts with each other and gain the lifespan of the longer lived between them. However, this also means that their lifeforces are linked. If one grows sick so does the other and if one dies, so does the other!