Diana wants to kill Leona because she worships the sun, but Leona knows that the sun and moon are both necessary. She really doesn't care that Diana worships the moon and wishes they could just get along.
Lux is looked down upon by Garen because he got to see inside her mind during her judgment, and he saw that she used to hate Demacia. This makes Lux really sad and she wishes she could have a better relationship with her brother.
Urgot wants to die, but he's afraid that if he kills himself, Noxus will just bring him back to life again with an even worse body.
During Riven's estimated 7 years(?) of exile, she traveled all over Valoran and happened to see a lot of awesome things (i.e., Leona's solar flare before she joined the League, Lee Sin setting himself on fire in Ionia, Alistar's gladiatorial fights in Noxus, one of Vi's robberies in Piltover, Skarner's emergence at the Crystal Scar, etc.). A book from her perspective would be awesome.