S.D. Codified Laws § 55-18-19
In a judicial proceeding, if the court determines that a person cannot be adequately represented by a representative, the court may order that the person be provided notice or may order the appointment of a court representative or a replacement court representative to bind the person. The basis for a finding that representation is inadequate shall be set forth specifically in an order and may include, by way of example, a finding that a representative has a material conflict of interest or acted with hostility to the interest of the person represented.
A trustee, a beneficiary, or, if authorized by the governing instrument, a fiduciary other than a trustee, may petition the court for the appointment of a court representative. A court representative has the authority to act as a representative in any proceeding unless otherwise ordered by the court.
Notwithstanding § 55-18-5, the court may appoint a court representative to bind uninterested beneficiaries, unborn persons, unascertained persons, or the potential appointees or the takers in default of a power of appointment.
Notwithstanding § 55-18-20, the court may appoint a court representative to bind a settlor.
SDCL 55-18-19