Is it better to store index list or object itself ?

First of all, sorry for the mistakes, english is not my native tongue.

I will try to explain clearly my question :

I have a class, named "character", w$$anonymous$$ch contain informations about my characters, like first name, surname, etc...

All existing characters are stored into a list, named "charactersList", and each time i create a new character, i add it to t$$anonymous$$s list. Like t$$anonymous$$s :

 public class Character : MonoBehaviour {
         
         public static List<Character> characterslist;
     
         public Character()
         {
     
             characterslist.Add(t$$anonymous$$s);
             
         }

I want to create a variable 'father' who contain a reference to another character. Knowing that I will never sort the 'characterList' list, is it better to store the index list in the variable 'father' or directly the character ?

Here is an example : I have my character Luke that i just created, and i want to store $$anonymous$$s father Anakin who's stored at index 42 in the 'characterList'.

Should i do :

   Luke.father = 42;

Or

 Luke.father = characterList[42];

Hope i'm clear and thanks for your help.