There is a Midnight Master in each of the LoRD realms. It may be male or female (but does not answer romantic mail), and fights with a bizarre weapon whose name is occasionally changed by tmo. Coconuts of Power and Flyswatter are two iterations of MM's massive weapon.
MM is always a level 1 character, with 2 exp. Her strength is minimal so she can't hurt you, but her defense is astronomical. She is always listed as alive, and she is not supposed to be killable.
MM's primary purpose in the game is to perform midnight maintenance in the realms, as the day-end bot. At midnight Nuklear time, Midnight Master comes by and logs into each realm one by one in order: Blue, Green, Red, Test. Logging in at midnight prevents a bug where multiple people log in simultaneously, causing multiple days to go by. While Midnight Master is logged in anywhere, nobody else may enter any realm. As soon as Midnight Master is no longer logged into any realm, then all realms open for play that day.
As long as all three colored realms are still in play, then midnight master can be counted on to log off at exactly 00:03:00. If one or more of them have closed due to a win, then MM will finish her task 45 seconds earlier per closed realm.
The other purpose MM serves is to force a stats refresh. Often, players who want to have an online duel will mock-duel MM first, which forces the game to make sure it knows their correct stats. Players who have leveled up and/or upgraded their equipment will especially want to force a stats refresh so they can be sure to benefit from the advantage they worked for.
To mock duel Midnight Master, simply go to the (S)laughter screen from the Town Square, type in her name and agree that she's the one you want, but then say (N)o to actually fighting. Voila, instant stats update.