BrutusMUD offers 4 basic classes from the beginning, 
however at level 30 you specialize into one of 3 advanced 
classes (3 for each basic class).
After reaching level 60 you can advance to legendary levels
which offers new skills and spells and generally greatly
enhances your character. To reach 5th legendary level, you
have to come through special challenge, which will test your
knowledge of your character. Thus only the best players can
ever reach 5th legendary level. Of course you can try until
you learn enough to succeed.
Successfully completing the challenge opens whole new range
of possibilities to advance your character far beyond limits
of lower legends. But only few reached this status, and they
are honored as gods among other mortals.