S.D. Codified Laws § 22-48-2
A perpetrator assumes the risk of loss, injury, or death resulting from or arising out of a course of criminal conduct involving a crime, as defined in this chapter, engaged in by the perpetrator or a person who aids or abets the perpetrator, as defined in § 22-3-3, and the crime victim is immune from and not liable for any damages as a result of acts or omissions of the victim if the victim used reasonable force. However, the perpetrator's assumption of risk does not eliminate the crime victim's duty to protect against conditions upon the premises which the crime victim knows or has reason to know may create an unreasonable risk of harm or which may cause a foreseeable trespass by minors, nor does the assumption of risk apply to perpetrators who are mentally incompetent.
SDCL 22-48-2