python – sudden interruption of the loop

I continue to master the basics of programming by coming up with a game. The error is related to the interruption of the loop when the length of the list reaches 3 item. If lenght of my list == 3 the loop is interrupted.
I do not understand what’s the matter.part of the code is working. copy, press 2 to start the cycle and press 1 until the length of the list becomes 3

    class Hero():
    def __init__(self, name, level, race, position):
        self.name = name
        self.level = level
        self.race = race
        self.position = position
        self.maxhealth = 1000
        self.health = 1000
        self.damage = 300

    def walk(self):
        self.position += 1

    def attack(self, name_enemy):
        name_enemy.health = name_enemy.health - self.damage
        if name_enemy.health <= 0:
            name_enemy.health = 0
            return name_enemy.health
class Enemy():
    def __init__(self, health, damage, race):
        self.health = health
        self.damage = damage
        self.race = race
        self.position = 1
enemys = ()

for obj in range(5):
    obj = Enemy(200, 50, "Орк")
    enemys.append(obj)
for obj in range(5):
    obj = Enemy(200, 50, "Человек")
    enemys.append(obj)
for obj in range(5):
    obj = Enemy(200, 50, "Гоблин")
    enemys.append(obj)
Pers = Hero("test", 1, "Человек", 0)
def action():
    if enemy.position == Pers.position and Pers.health > 0:
        while Pers.health > 0:
            answer = input(f"""
_______________________________________

Нажми '1' Атаковать!!!n
_______________________________________
n Твой ответ?tt""")
            if answer == "1":
                if enemy.health > 0 and Pers.health > 0:
                    Pers.attack(enemy)
                if Pers.health <= 0:
                    print("text for testing2")
                    break
                if enemy.health > 0 and Pers.health > 0:
                    enemy.attack(Pers)
                if enemy.health <= 0:
                    print(len(enemys))
                    for i in enemys:
                        print(i.race)
                    enemys.remove(enemy)
                    print(len(enemys))
                    for i in enemys:
                        print(i.race)
                    break
    if len(enemys) == 0:
        print("Врагов не осталось!!!")
        print(f"{Pers.name} Ты победил!!!")
######################################START_GAME##############################################################
while len(enemys) > 0 and Pers.health > 0:
    for enemy in enemys:
        if len(enemys) > 0 and Pers.health > 0:
            action()
    if len(enemys) <= 0 or Pers.health <= 0:
        print("text for testing1")
        break
    answer = input("""
    Нажми '2' Двигаться впередn
    Твой ответ?t""")
    if answer == "2":
        Pers.walk()
        for enemy in enemys:
            if len(enemys) > 0 and Pers.health > 0:
                action()