In the early years of League of Legends, lore was fairly well maintained and made sense. Riot managed to come up with a interesting and sensible explanation for a MOBA game. Players were "summoners" and each battle was a match within a "field of justice". There was also a war going on between Noxus and Ionia, which concluded in an event match actually played by players. The Journal of Justice gave interesting insight to the world at large, where champion biographies couldn't.
Then came the end of JoJ. I'm not sure if anyone has brought this up with Riot yet, but their champion backgrounds are getting extremely ridiculous. Champions are beings that possess considerable combat ability, accepted by the League to participate in arena matches that decide the outcome of various political conflicts. It's a neat system that removes war from the world and all the destruction it brings. Champions join the League for many reasons: fame, profit, challenge. Some are employed by the League itself, such as Kayle or Nasus. Some are dangerous beings imprisoned and used for League matches (rather than letting them collect dust in their cages).
Then there are those that make me think, "Why the fuck are they in the League?" And these champions are all recent additions. Bear in mind that I'm working off their canon background info only as I can't remember/can't find additional lore info they sometimes add for certain champions. So correct me in the comments if I get anything wrong.
Syndra
Criminal. She murdered her mentor and stole an entire school, announcing to the world that she would destroy all that stands in her way. This is where her bio ends. Unless the League captured and imprisoned her like many of the Void champions, why would they allow a power-mad criminal to become a champion?
Yasuo
Again, wanted murderer of several lives.
Thresh
Is the Institute of War allowing him to collect the souls of champions on the fields of justice? I don't really see how they're going to have anyone left after a while.
Ancient evils and dangerous creatures have always been locked up in the past. Are we to assume the same applies to the newer "evil" champions? Or is the Institute of War just extremely whimsical and doesn't give a damn about politics or public morals? Even if either were true, there is one champion that no explanation can salvage:
Lissandra
She's an ancient evil that is supposed to be impersonating the leader of the Frostguard clan, subtly corrupting them throughout the ages to prepare for the return of the "Watchers". Pray tell how is she revealing herself to the Institute of War? How does she escape suspicion when she has to disappear every now and then for a match?
Please discuss and enlighten me.