This subject has always fascinated me.
1 - In one month you will fight empty-handed to the death (literally) against an adversary you know nothing about. No gear, no referee, no rules. Someone will die.
how would you train?
There is a story (I think I've told this one before) of a tea master who found himself in just this position, except he only had a week to prepare for a duel with a Samurai warrior. So, he went to a warrior friend of his to ask for help in training for the fight. His friend said no way can it be done - not enough time to teach your body. But he pointed out to the tea master that he was already trained in spirit. "Just approach the duel as you would tea ceremony." So on the day of the duel the two combatants approached each other. The Samurai saw the calm serenity and presence of mind of his opponent and was so shaken, he fled.
So, in the absence of technique, spirit can be an equalizer. Of course, the tea master was a "master" to begin with. For most
untrained people in this given scenario, I would suggest the following 30 day (every day) training regimen:
#1. Accept the fact there is a good chance you'll die and get comfortable with it.
#2. Practice a single technique - a hand feint to the head and a knee breaking / wrenching kick would be my personal choice.
#3. Foster a fighting spirit - attack a heavy bag intent on killing; break and rip things apart with hands, teeth, head and feet and fingers.
Approach the fight with #1 with a look that says "I'm ready to die.".......... Execute #2........... Regardless of the results, proceed to #3.
Given the parameters of the scenario, I think this plan would give an untrained person the best shot. For trained people there are more options - I'll leave that to other posters.