Hunter x Hunter is probably one of my very favorite stories of all time. Excellently written, it's a deconstruction of typical shonen tropes. Every arc and character has a purpose in the overall story, and it is one of the few stories where the protagonists and antagonists are equally compelling. The main narrative six characters (Gon, Killua, Kurapika, Hisoka, Illumi, and Chrollo) all foil each other in very interesting ways, and the story can veer from lighthearted adventure to dark ponderings on the evil humanity is capable of without even feeling uneven. The framing is excellent and the story's themes are powerful.

It has great female characters (my only complaint about HxH is that there were no female characters until Yorknew Arc, but after that, they're there and they're awesome and thematically relevant with powerful arcs--especially Palm, Neon, Oito, Komugi, and Alluka). Speaking of Alluka, she is great trans representation. In general, the side characters are highly compelling.