By the time he accumulated enough XP to reach 3rd level, Kujo Jotaro's player decided that instead of taking another Fighting Man level, he was going to multi-class and become a Fighter/Stand-User instead. Irritated, his DM told him that he would have to travel to Egypt to fight a Vampire for his Milestone Objective.
This idea is largely stolen from Dungeon Craft and Index Card RPG.
The Referee should assign every Adventure or Quest a difficulty rating, based on how hard it is.
A Difficulty of 1 means the Quest is easy, something you can accomplish with minimal effort. An example of a Difficulty 1 Quest is when Bruce Wayne infiltrates Lex Luthor's house to steal data from his computer network, or figure out who, or what, the "White Portuguese" is.
A Difficulty of 2 means the Quest is difficult, something the players can accomplish with difficulty. An example of a Difficulty 2 Quest is when Clark Kent must destroy the World Engine in Man of Steel, or how Diana Prince decides to cross No Man's Land and liberates the French Village from German occupation in Wonder Woman.
An Difficulty of 3 means the Quest is extremely difficult to borderline impossible, something that could wipe out the players entirely and has disastrous consequences should they fail. An example of a Difficulty 3 Quest is when Batman, Superman and Wonder Woman must team up to fight Doomsday at the end of Superman v Batman or when Blackstar escapes and needs to be brought down in Jupiter's Legacy.
If the players succeed and finish the Quest, assign experience whenever you normally do. I do it at the beginning of the next session, but it doesn't matter. Depending on the Difficulty of their last Quest, give them a number of experience points equal to the Difficulty Rating. So, for instance, a Difficulty 2 Quest earns 2 Experience Points.
Alternatively, you could give a Quest multiple objectives and assign an XP point to each one. For example, if the Quest is to rescue the princess from the Orc camp and kill the Chieftain, that is a Difficulty 2 Quest, with 1 experience point per successful objective. Killing the Chieftain nets you 1 point, while saving the Princess nets you another.
Or you could just make the objective to rescue the Princess and if the players want to kill the Chieftain to get his axe that boils blood - they can do that as well. It's your call as the Referee.
When the players accumulate 10 Experience Points, then they can no longer gain any Experience, but are eligible to complete a Milestone Objective. Once they complete their Milestone Objective, they level up and their Experience Points reset to 0.
A Milestone Objective can be anything, but it should be A) difficult and B) a test of the skills and abilities the character already has.
The Level 1 Fighting Man's Milestone Objective is that he has to fight a powerful (as strong as him or stronger) monster in single-combat and win.
The Level 1 Sage's Milestone Objective is that he steal a Crystal Ball from a the Hag who lives in the center of the Black Mire.
The Level 1 Scoundrel's Milestone Objective is that he has to commit a new type of crime.
The Level 1 Prophet's Milestone Objective is that he has to find the undercover cultist in the King's court and expose him.
And as the characters increase in level, the Milestone objectives should be more difficult. Maybe the Fighting Man only had to kill an Orc Chieftain in a duel at Level 1, but at Level 3 he has to beat a Spirit in a wrestling match and at Level 7 he has to defeat 100 men with only his sword and trusty dagger.
You can also customize the Milestone objectives to fit the specific player character. If the Artificer is the exiled Marquise of Rowan, then perhaps his Milestone objectives can be about him going on various quests to gain support for an invasion of his occupied homeland and eventually to reclaim his ancestral seat.
|from JoJo's Bizarre Adventure: Stone Ocean|
By the time he reached 7th level, Kujo Jotaro's player thought he had seen it all, but even he was surprised when his DM busted out the black Italian priest with the power to accelerate time and move at ludicrous speeds; then told him that he would have to feed said Priest his fist if he wanted to reach 8th level.