what character should i get?

Is there any character that I MUST get on my account?

if I dont get Wriothesley, probably I will save for Yae Miko (I just like the character, ik she isnt the strongest and all but i loved her in the story and her design), Nahida (I dont have a decent Dendro character) or Citlali (i want to melt with Arlecchino)