ToME: the Tales of Maj'Eyal

I've completed 'the agent of the arena' quest and unlocked arena mode. The arena is supposed to be in SE of Derth, but there is no access portal or such. How do I access arena mode?

Thanks in advance for your replies / suggestions.

The Arena is a separate campaign you choose at character creation. It gives a different game mode where instead of exploring the world you fight waves of enemies and rise quickly through the levels. It's a good way of testing new classes and different character builds.

Thank you for the info. I wonder if future game versions will incorporate it into the main game.