1) venture to Hostile Grounds and find the Hostile Guard at the final map. Equip your Hostile Costume and Hostile Headgear and talk to the Hostile Guard to enter the Hostile Village. At the center of the map is the Hostile Chief. Talk to him and he'll send you off to find a Horrid Mask.
2) Return to Oriana at Aman Jungle village and say "Ugliest mask" twice outloud. She will give you the Horrid Mask in exchange for 20 Crystal bars.
3) Hand over the Horrid Mask to the Hostile Chief and he'll mention his plans for Aman Jungle, as well as giving you a fourth legend mark.
4) while still at the hostile chief, Say "tell me the plans" outloud to Hostile Chief to hear some backstory between him and the Aman Jungle chief. After listening to his story, return to Vortigern at Aman Jungle village. Vortigern will tell you to return in one day to receive his Apology Note.
5) wait 24 hours
6) After receiving the Apology Note from Vortigern, return to Hostile Village and find a place to hide it. (WANDER AROUND EVERYWHERE.) I got a pop-up to hide mine at 57,61 but this may be different for everyone. After hiding the note, return to the Hostile Chief and say "received the note" outloud. He will tell you about the note he found and his plans to visit Aman Jungle.
7) Return to Vortigern and tell him the news. You will receieve another legend mark. AJ quests completed
