How to organize links in a database?

Question

Django

There is such a model

# Эта модель хранит всех героев , в том числе и активных, но с меткой hero_active = True
class UserAllHero(models.Model):
    user_hero = models.ForeignKey(User, on_delete=models.CASCADE)
    #hero_equip = models.OneToOneField(HeroInventory,on_delete=models.CASCADE)

    hero_name = models.CharField(default='Герой', max_length=32)
    hero_image = models.ImageField(upload_to='hero_img', default='')
    hero_life = models.IntegerField(default=20)
    hero_armour = models.IntegerField(default=20)
    hero_damage = models.IntegerField(default=120)
    hero_xp = models.IntegerField(default=0)
    hero_level = models.IntegerField(default=1)
    hero_unique_id = models.CharField(default='unique_id', max_length=48)
    hero_class = models.CharField(default='Класс', max_length=32)
    hero_badge = models.ImageField(upload_to='badge',default='')
    hero_power = models.IntegerField(default=25)
    hero_points = models.IntegerField(default=10)

    life_points = models.IntegerField(default=0)
    armour_points = models.IntegerField(default=0)
    damage_points = models.IntegerField(default=0)
    hero_active = models.BooleanField(default=False)

    weapon_one = models.OneToOneField('UserInventory.UserInvWeapon', on_delete=models.CASCADE, related_name='weapon1',blank=True,null=True)
    weapon_two = models.OneToOneField('UserInventory.UserInvWeapon', on_delete=models.CASCADE, related_name='weapon2',blank=True,null=True)
    helmet = models.OneToOneField('UserInventory.UserInvHelmet', on_delete=models.CASCADE, related_name='helm',blank=True,null=True)
    cuirass = models.OneToOneField('UserInventory.UserInvCuirass', on_delete=models.CASCADE, related_name='chest',blank=True,null=True)
    pants = models.OneToOneField('UserInventory.UserInvPants', on_delete=models.CASCADE, related_name='pant',blank=True,null=True)
    gloves = models.OneToOneField('UserInventory.UserInvGloves', on_delete=models.CASCADE, related_name='gloves',blank=True,null=True)
    boots = models.OneToOneField('UserInventory.UserInvBoots', on_delete=models.CASCADE, related_name='boot',blank=True,null=True)

    def __str__(self):
        return self.user_hero.username

It stores the user's heroes, as well as links with items from other tables (those in this case are typical inventory as in rpg games)

, here is a model with weapons

class UserInvWeapon(models.Model):
    user_weapon = models.ForeignKey(User, on_delete=models.CASCADE)
    

    user_weapon_name = models.CharField(default='Меч', max_length=60)
    user_weapon_level = models.IntegerField(default=1)
    user_weapon_damage = models.IntegerField(default=50)
    user_weapon_inc_damage = models.IntegerField(default=10)
    user_weapon_rarity = models.CharField(default='common', max_length=32)
    user_weapon_img = models.ImageField(default='shop_sword', upload_to='shop_sword')
    user_weapon_status = models.BooleanField(default=False)
    user_weapon_unique_id = models.CharField(default='un_id', max_length=64,primary_key=True)
    user_weapon_class = models.CharField(default='класс оружия',max_length=64)

Actually a question, - How to me it is correct to organize communications in this case? so that each hero can only equip 1 weapon from the table, and if a weapon is worn by any hero, do not give the opportunity to put on another hero.
And in the future, on the inventory page, do not display items associated with any hero.
It seems like OneToOne itself limits such possibilities, but apparently I need something like reverse-relationship in order to find already associated with some hero in the UserInvWeapon

model Thank you