Go to the practice arena, ASK ERATIUS FIGHT, ASK ERATIUS YES, and ASK ERATIUS I CHALLENGE GLADIATOR.
Say that and he tells you to come back in 1 mud hour.
Wait in the room and Eratius will open the door in 1 mud hour.
Move south into the practice arena and names a gladiator you will fight.
Kill the gladiator, careful there are a bunch of gladiators here and using keyword gladiator can lead to a you attacking the wrong one.
After you kill the practice gladiator, the gate keeper asks you if you want to continue on into a much harder fight.
Proceed to the main arena. Once you go inside the gate locks and the main gladiator is agg to you along with one of the arena animals (bear, wolf, cat, lioness).
Kill both of them and you get the whois.
Please note: that you may be able to do this and lose. I was stunned and taken to 25 health, the fight ended, I lived and still got the whois. Also, the gladiator will hunt you inside but can not see invis. The bear will not move from the gate. seperate them and kill the bear so you can pick the lock to the gate. open the gate and the gladiator will not hunt you into the entrance ramp into the arena.