[Source] The Antiviral kit MK-1 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-2 and MK-3 where more powerful versions of the MK-1. Captains Erimus Moayoi and Lahoa Diatog of THORN sold Antiviral kit MK-1s.