The relative’s visa is intended for applicants who are within the first step of kinship to a South African citizen or a permanent resident. Except for siblings, grandparents and grandchildren, the second step of kinship, unfortunately, does not apply to the relative’s visa. This means that you cannot apply for this visa under your South African uncles, aunts or cousins.
This visa would require the South African relative to sponsor the applicant. Relative’s permits are valid for a period of 24 months and can be extended. If you enjoy staying in South Africa so much that you want to make it permanent, under the first step of kinship (your partner/spouse/life partner) you will be able to apply for permanent residency.