I wish Bungie will give us D2 Compendium like the Persona series. Persona has this game mechanic where you collect monsters and register them in the Compendium. It saves the monster's traits and levels. You can re-aquire these monsters anytime. For example: Your first pixie can evolve(fusion between several monsters) into an all powerful high angel Metatron but you still have a copy of your first pixie in the compendium. If we have a D2 compendium, I can promise Bungie, I'll only be keeping 7 weapons in my vault!