https://qiita.com/TP-faure/items/4c48fa919522aec0ae6d#comment-476704a94f9079083f1e

rpg.py

import random


class Character:
    def __init__(self, name, hit_point, attack_power):
        self.name = name
        self.hit_point = hit_point
        self.attack_power = range(attack_power + 1)

    def is_dead(self):
        return self.hit_point <= 0

    def attack(self, defender):
        print()
        print(f'{self.name}の攻撃！')
        defender.defense(random.choice(self.attack_power))

    def defense(self, damage):
        if damage <= 0:
            print(f'{self.name}は攻撃をかわした！')
            return
        print(f'{self.name}は{damage}のダメージを受けた！')
        self.hit_point -= damage
        if self.is_dead():
            print(f'{self.name}は力尽きた')


MONSTERS = [
    Character('スライム', 10, 1),
    Character('ドラキー', 13, 2),
    Character('ダークドレアム', 130000, 999),
]


def main():
    hero = Character('勇者', 30, 5)
    monster = random.choice(MONSTERS)
    print(f'{monster.name}が現れた！')

    attacker, defender = hero, monster
    while not attacker.is_dead():
        attacker.attack(defender)
        attacker, defender = defender, attacker

    print()
    if monster.is_dead():
        print('勇者は戦闘に勝った！')
    else:
        print('勇者は戦闘に負けた！')


if __name__ == '__main__':
    main()