MerchantBehaviour.cs

using UnityEngine;

public class MerchantBehaviour : MonoBehaviour, IMerchant
{
    [SerializeField]
    private InventoryBehaviour inventoryBehaviour;

    [SerializeField]
    private MerchantRaces race;

    [SerializeField]
    private string name;

    void Initialize(string id, string name, MerchantRaces race, IInventory inventory)
    {
        Id = id;
        this.name = name;
        this.race = race;
        inventoryBehaviour = null;
        _inventory = inventory;
    }

    public string Id { get; private set; }
    string IMerchant.Name { get { return this.name; } }
    MerchantRaces IMerchant.Race { get { return this.race; } }

    private IInventory _inventory;
    IInventory IMerchant.Inventory 
    {
        get 
        {
            if (inventoryBehaviour != null) return inventoryBehaviour;
            return _inventory;
        } 
    }
}