Attohwa Chasm, even with a map, can be very confusing. Monsters in the central and eastern areas tend to be non-aggressive to level 60+ characters, while monsters on the west side of the map (the side that Tiamat and Xolotl spawn on) will still be aggressive to a level 75 character.
Cross the bridge (this is very important) and follow the path.
At (H-10) there is a dead end. You want to head east, not west. This will take you into the lower leveled eastern side of the map.
Follow the mountain side north to (I-8). There is a cave to take you back into the mountain/chasm area.
Follow the path (there is another dead end shortly into the area, head south not north). The path winds in all directions and takes you all over the chasm. There will be a fork in the path, follow either one south.
At (G-7), there is another dead end; head north, not east. You will cross three bridges before you get to the end.
Be very careful once you see the tunnel exit, as Antlions come very close to the mountain. Use Sneak and Invisible and follow the mountain north again.
A mysterious character living on Purgonorgo Isle in Bibiki Bay insists that the island belongs to him. Chipmy-Popmy wants you to participate in the next "debate" over ownership, set to take place in the center of the island.