Advancing HP: There are three types of HP advancement types regarding classes. Fast, Medium, and Slow. Fast progresses at a full rate of +1 per level, Medium progresses at a ¾ progression (skip 2nd level, 6th level, 10th level, etc.), and Slow progresses at a ½ progression with a +1 at every odd level.
Despite advancement, HP will be relatively low during combat and enemies and players alike have an easy time killing one another. This is intentional.
Awarding EXP: Defeated enemies are worth a number of EXP equal to their level times 250. For example, a level 4 character is worth 1,000 EXP when defeated.
At higher levels, there are diminishing returns for fighting lower level enemies. These reductions are factored in after the total EXP earned has been divided by player. Thus if a party has uneven levels among characters, the lower level characters are not penalized.
EXP Chart: EXP resets to 0 after advancing to the next level. Therefore a level 18 character who gains 38,000 EXP resets to 0 and must earn 40,000 to become level 20.