Use the chat command "-unlock" to disable the hero level requirements for anything.
The highest level of your heroes determines which features are available for you:
5: Abilities available on Theramore.
10: Random Events.
15: 1 Equipment Bag on Goblin Bank Island.
20: Mount.
25: Second profession.
30: Bonus races.
35: Hand of God and Hidden Bases.
40: Bonus heroes and 2 equipment bags.
45: Second hero and third profession.
50: Boss heroes.
55: Boss Fight Island.
60: Second race and 3 equipment bags.
65: Third hero and third race.
70: AI for yourself.
75: Void Lord can be chosen as hero who can learn different spells.
75: Advanced chat commands from "-helpvisual" can be used.
75 (all 3 heroes): All races and professions are available and chat command "-maxbosslevels".