After maximum level, characters gain a number of hit points (plus applicable constitution bonuses)
Cavalier 3
Paladin 3
Cleric 2
Druid no limit on dice
Fighter 3
Barbarian 4
Ranger 2
Magic-User 1
Illusionist 1
Thief 2
Assassin no limit on dice
Monk no limit on dice
Bard 1