S.C. Code Ann. § 62-3-811: Counterclaims.

In allowing a claim, the personal representative may deduct any counterclaim which the estate has against the claimant. In determining a claim against an estate, a court shall reduce the amount allowed by the amount of any counterclaims allowed and, if such counterclaims exceed the claim, render a judgment against the claimant in the amount of the excess. A counterclaim, liquidated or unliquidated, may arise from a transaction other than that upon which the claim is based. A counterclaim may give rise to relief exceeding in amount or different in kind from that sought in the claim.