Heh i see what you mean, but i don't agree that he makes an art out of his trail of death. I sort of imagine death was the side effect of his art. He strives to create perfect art when he tries to create perfection from his muses, their death is an insignificant consequence of the perfect art he's made in his eyes. The fact he wears a mask may imply he doesn't see himself as perfect, or he disgraces himself and the mask is the only way he can cope with his own imperfections: by hiding them away.
However, Jhin targets other peoples' imperfections. Vi's hands, Garen's ambivalent heart, Zed's shamed face, and sona's nonexistant voice. These people all share in how they conceal or try to make up for their flaw. Garen's armor protects his heart, zed's mask and shadows hide his shame, Vi's hands empower her to protect what she feels are important, and sona uses her Etwahl to speak for her. With Jihn's obsession with perfection he may target these people because they remind him of his own shame his making them perfect is sort of his way with coping with himself or rectifying his own flaws.
Well i'm down rambling for now.