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.
This is a generic detection for a special kind of Trojan that changes users’ DNS settings on his system and that it require some actions to undo the changes:
Malwarebytes can remove these threats completely without any further action of the user. A reboot of the system immediately after threat removal finishes is required though. And the user will be prompted to do so.