Since the 4th millennium BC (and likely before), humans have been inking patterns and motifs directly onto their skin. Reasons for doing something so painful and permanent range throughout place and time. Some do it for spiritual, religious or cultural reasons, while others are rejected by society if choose to get inked. People get tattoos to commemorate people and events, as reminders, and sometimes simply because it looks cool. Anime and manga are popular tattoo themes nowadays as their illustrative nature makes for easy translation from paper or TV to needle.
Hunter X Hunter in particular lends well to the inking scene due to its many tattooable motifs like the Phantom Troupe spiders or Kurapika's chains. And what anime-loving duo wouldn't want a matching Gon and Killua tat? I am personally partial to any sort of manga panel tattoos, and Yoshihiro Togashi is so talented and creative that many of his illustrations would look great on skin. Enjoy this collection of HXH tattoos! Just remember that if you decide to get inked up, it won't come off as easy as Hisoka's Phantom Troupe spider tattoo.