An idea that would be easy to implement and would VASTLY increase exposure and depth to lore
Why don't we have more quests? People will say hurr durr they impact balance, but it would be VERY small. As long as it matters a teensy bit, I think Iit would be cool. For example, if Lucian is against a shadow isles character and he kills them X amount of times, he gets a bonus 200 gold. ATM because they are sooo focused on balance, the only quests are super small (like zilean gets 10 extra gold from killing volibear, or the khazix rengar thing). Honestly, there are only two reasons NOT to do this
1 - Riot is lazy and doesnt want to take like a day to code this in (no new animations or kit changes, just some bonus golds or stats and maybe a quote, for big rialries like lucian and thresh and sion jarvan put a little extra effort)
2 - they are SO concerned about balance that they wont even make small changes
Off the top of my head, I can list (and vice versa):
Kass vs void champs
Sion vs jarvan or Galio
Garen vs kat
Darius and draven get a small bonus from being on the same team and assiting each other
Zed and syndra vs kennen, shen, and akali
Sej, voli, udyr vs Ashe trynd and braum vs liss and trundle
Trynd vs aatrox
lucian vs SI champions
etc etc etc
Upvote if you think this is a good idea, maybe a Rioter will see this (Bio im counting on you!)