User blog comment:EasleyAmused/Lucian and Lore/@comment-5035765-20130709075650/@comment-11746882-20130709203556

Actually I believe Nautilus triggers those, as stated on the wiki. If you go to Thresh's background and scroll down to that quote, it says he says that around Nautilus. I find it interesting that they interact, however, so Thresh must be pretty high up in the ranking of the Shadow Isles. He must know what happened to Nautilus.