Problem with passing object to another script.

Hello, I created custom class called Monster (to contain Monster data). After that I created MonsterDatabase class where I want to store all Monsters. Here is my database code:

 public class MonsterDatabase : MonoBehaviour {
 
     public List<Monster> Monsters;
     List<Item> items;
     
     void Start () {
         Monsters = new List<Monster>();
         items = GameObject.FindGameObjectWithTag("ItemDatabase").GetComponent<ItemDatabase>().Items;
 
         Monsters.Add(new Monster("InitialMonster",
                                  100,
                                  25,
                                  15,
                                  0,
                                  5,
                                  MonsterType.BEAST,
                                  RarityType.UNCOMMON,
                                  AttackType.CRUSHED,
                                  new List<Item>(){items[0], items[1]},
                                  new List<float>(){0.90f, 0.50f}));
     }
 }

Everything is okey, I can see all values and Lists with Items & chances to loot them in inspector after starting game.

Now I want to spawn Monster which will have in script MonsterController copy of that monster created in Database. I have that:

 Monster monster;
 void Start () {
     monsterDatabase = GameObject.FindGameObjectWithTag("MonsterDatabase").GetComponent<MonsterDatabase>();
     this.monster = monsterDatabase.Monsters[0].GetMonster();

     //Die();
 }

where GetMonster() is method inside Monster Class to get copy of it:

 public Monster GetMonster()
 {
     return new Monster(this.monsterName, this.experience, this.health, this.defense, this.damageFrom, this.damageTo, this.monsterType, this.rarityType, this.attackType, this.lootItems, this.itemProbability);
 }

Unfortunatelly inside MonsterController monsterDatabase seems to be empty. I don't know why cus i can see it have "InitialMonster" when I open it in inspector. Can someone tell me what I am doing wrong? If I am not clear please leave a comment, I will try to explain my problem better.