The Antiviral kit MK-3 was manufactured by The Hyland Organization for Rakghoul Neutralization (THORN). It provided temporary immunity to the rakghoul plague as long as it was equipped. The Antiviral kit MK-1 and MK-2 where weaker versions of the MK-3. Captains Erimus Moayoi and Lahoa Diatog of THORN sold Antiviral kit MK-3s.