Speak to the Villager located outside the hotel. He tells you about a man he never sees neither eating nor drinking but can work all day long. Head out of the North Exit of the town. Continue to the North exit of that map. Head to the landmark (?) symbol located on your map. Talk to the man there and he will attack you. When you defeat him he begs to stay on planet Earth. Return to the villager in Cairo and talk to him to receive your reward.
[Martian, LVL:120-130, HP:8500-9500, Fire & Earth] * 2
Reward: 1000 EXP, 3% EXP Bolus, Star*1