A Hero's level generally represents their overall skill, experience, fame and power. A Hero starts out as a fledgling adventurer at Level 1 and as they complete quests and adventures they may increase in level. As the Heroes increase in level they may improve their SKILLS.
Upon the completion on a successful mission or adventure (at the GM's discression), a Hero has been deemed to have received enough experience from their heroic actions that they increase their level by one.
To gain a level a Hero must pay a training fee. This fee is equal to 100 times the Hero's current level in gold coins. The Hero must spend time training equal to a number days equal to the Hero's current level.
The Hero must seek out and locate a trainner, guild or individual to increase a single SKILL and attain a new level.
Here are some example trainners or guilds to for the Heroes to attend, depending on the SKILL the Hero wishes to increase.
Can provide training in the following Skills: Agility, Roguery, Awearness, Dark Sight
Can provide training in the following Skills: Might, Endurance, Swordplay, Brawl
Can provide training in the following Skills: Agilty, Wilderness Lore, Marksmanship
Can provide training in the following Skills: Craftmanship, Charm
Can provide training in the following Skills: Magic, Magic Resistance, Folklore
Can provide training in the following Skills: Healing, Magic, Magic Resistance
For example, Rastan the 5th level Barbarian has successfully completed and adventure and the GM agrees that Rastan has earnt enough experience to go up a level. Rastan's player chooses to increase Rastan's Might. The GM notifies the player that Rastan may spend 5 days training and spend 500 gold coins training at the local Fighters Guild to increase Rastan's Level by one and increase his Might Skill by one.
Leveling up can continue as far as the GM wishes - there is now limit on what level a Hero (or monster) can attain. This also keeps the Heroes looking for jobs, hunting for and selling treausure. Just remember tougher Heroes need tougher enemies.