Trojan.Agent refers to a generic Trojan malware detection. It is used for detections that are either associated with no specific malware families or not enough information is available to pinpoint the malware family.
Trojan.KillAV is a generic detection for Trojans that are capable of disabling antivirus (AV) programs.
Malwarebytes protects users from Trojan.KillAV by using real-time protection.
Malwarebytes can detect and remove Trojan.KillAV without further user interaction.
Depending on the AV software being disabled and the method of doing so, users may have to re-install the affected software.