My take on Jhin based on new info.

With everyone making theories and especially a new teaser coming out I decided to make my own theory. Jhin is a perfectionist. He is obviously delusional and wants everything to be perfect, therefore he sees everything he does is beautiful, whether death or killing he sees it as a work of art. However due to his state of mind he sees himself as ugly, which is why he wears a mask, he wants to hide the fact that he's nothing like what he imagines everything to be. So I have a theory according to this. He's an assassain. Zed is a huge problem in Ionia due to disrupting and overthrowing the philosophy of balance. He's a threat, a huge one. Garen is a Demacian, who is in love with a Noxian. A Demacian, a public figure who leads with strength and justice in love with a person who is league with their mortal enemy. Sona a terrific musician with a magical Ethwal. Obviously someone who is jealous and wants the Ethwal for themselves. Vi, a huge threat to criminals. It wouldn't be uncommon for criminals to hire people to kill others. However Jhin won't take just any case, he takes cases where he can do some poetic justice as well as making their deaths beautiful and perfected. After all beauty comes from poetic justice. Zed? A ninja who became evil and wants to throw balance because he saw a box? Perfect! Shoot him in the eyes and make him perfect! Garen? A Demacian who shouts DEMACIA? Ehh normal. But a Demacian who's heart is captured by the enemy? Shoot him in the heart and he'll be a perfect victim! Sona? A mute who can play a magical instrument beautifully? Beautiful, shoot her in the throat and take her Ethwal. Now she seems perfect, no flaws. Vi? A criminal turned officer because of some gauntlets? Shoot her then burn her body! That way she's perfect! No trace she was anything else! His twisted mind sees this as perfection. A person with no flaws is a perfect person. All his killings make them somewhat normal now compared to what they were before. Shoot Zed in the eyes and expel the evil looks in his eyes. Make him perfect, and the picture shows it. Instead of obvious blood it's replaced with petals and branches. Garen? Shoot him in the heart so he can't love the Noxian anymore, now his heart can't be in the wrong place and he's just a Demacian who was a Demacian figure. The shards that make it seem beautiful are actually chunks of his armor and blood coming out. Sona? Shoot her in the throat, that way people can assume that's why she can't speak, she was shot in the throat. The butterflies are blood obviously. Vi? Shoot her then take her Gauntlets. Now she seems normal, perfect! Burn away her identity and make her normal. The pictures are literally showing us what's happening, it's what's happening from the mind of Jhin. It's what he sees when he kills, when he makes a person perfect. That's why they seem absurd. A plant coming out of Zed's eye? What happened? Zyra threw a branch into his eye? No, it's the delusional mind of a killer. A sociopath who wants everything to be perfect, who suffers from extreme Perfectionism. That's just my take on it. Hope you enjoyed reading it.