C# Decorator Pattern - Access Components Value

I am curently working on an example using the decorator pattern.

My model looks something like this: Model

The abstract class ICharakter is the interface for the classes to decorate:

public abstract class ICharakter
{
        public string Name { get; set; }
        public int HealthPoints { get; set; }

        public abstract AttackInformation attack();
}

The Component Knight inherites this class:

class Knight : ICharakter{
      public int KnightArmourPoints { get; set; }
      public Knight(string name, int healthpoints){
          this.Name = name;
          this.HealthPoints = healthpoints;
      }
      public override AttackInformation attack(){
         //implementation
      }

}

This is what the abstract Decorator-Class looks like:

abstract class CharakterDecorator : ICharakter
    {

        protected ICharakter Charakter;

        
        public CharakterDecorator(ICharakter charakter)
        {
            this.Charakter = charakter;
        }
        public override AttackInformation attack()
        {
            //implementation
        }
}

And my two Concrete-Decorator look something like this:

class Armour : CharakterDecorator
    {
        public int ArmourHealthPoints { get; set; }

        public Armour(ICharakter charakter) : base(charakter)
        {
            ArmourHealthPoints = 20;
        }
        public override AttackInformation attack()
        {
        //implementaton
        }
     }
class Amplifier : CharakterDecorator
    {

        public int AmplifyValue { get; set; }
        public Amplifier(ICharakter charakter) : base(charakter)
        {
            AmplifyValue = 10;
        }
        public override AttackInformation attack()
        {
            //implementaton
        }
    }

Now I create a Armour-Decorated, Amplifier-Decorated Knight:

ICharakter c = new Armour(new Amplifier(new Knight("John", 15)));

Now, when I call c.HealthPoints, I expect the object to return the given value 15. Instead, 0 is returned. Can anyone explain why, and how i get the programm to return the expected value 15? I am new to this topic and very thankful for every help I can get! If you need further information feel free to ask!