- This article is about the book. For the character, see Roque Ja.
Rock Jaw: Master of the Eastern Border is the fifth volume of the Bone series. It contains issues 28-32. The book follows the adventures of Fone and Smiley Bone as they return a baby Rat Creature to his kind in the Eastern Mountains. Along the way, they meet Roque Ja (they say it Rock Jaw), the master of the Eastern Border.
Fone Bone and Smiley have finally arrived to the Eastern Mountains. Smiley gives the rat creature cub they wanted to return to the mountains the name "Bartleby". Fone Bone keeps reminding Smiley that Bartleby is still a rat creature and had to be with his kind. As the Bones take a brief rest, The two stupid rat creatures that have deserted the others since The Dragonslayer plot to devour them for survival. As the two rat creatures approach Bartleby hisses, waking the bones of the rat creatures' presence. Fone Bone is able to distract them by readinghis book Moby Dick, which puts them in a temporary sleep.The Bones then uses the chance to escape and leave Bartleby to be with the two rat creatures. After waking up from their slumber, the two rats chase after the bones causing them to climb up deeper up the mountains. The bone cousins are trapped in a corner, as the rats come closer, Bartleby comes and defends them long enough for the cousins to chase the rats away by through rocks at them. Smiley sees the fact that Bartleby had saved them a way of seeing Bartleby was a possible ally. Fone Bone is now unsure what to do since their goal was to give Bartleby back, but seeing how he wasn't taken back he doesn't know what to do now, until a giant mountain lion arrives and sees the unusual group, the lion Addresses himself as "Roque Ja, Master of the Eastern Border. Roque Ja asks the group is with "them", Rose Ben and the Dragons or "Him", the Hooded One since the valley is at war and everyone must choose a side. Fone Bone tries to explain to Roque Ja that as strangers or bones they were not of the valley. After finding their surname is "Bone" he explains the Hooded one and his legions are looking for someone by the name of Bone who bears a star since he believes he will unite the valley after preventing it's conflict. Smiley expresses his own doubt knowing the one who bears the star is the name everyone has given to their cousin, Phoney Bone. Fone Bone asks Roque Ja what side had he chosen, he doesn't answer, saying the bones are in no position to ask any questions. The bones try to leave but Roque Ja pushes the cousins over the mountain, Fone Bone holds onto the ledge and Smiley grabs onto Fone Bone and holds onto Bartleby so he doesn't fall. Roque Ja begins to think of the possibilities of a reward for bringing in two bones and a runaway rat creatures, but brushes it off and orders the bones' to bring Bartleby up first, Smiley at first refuses and demands that Roque Ja leave them be, but Bartleby has Smiley bring him up for their safety.After Bartleby is brought up to the top, Roque Ja grabs both Smiley and Fone Bone so he wouldn't fall and jokingly says, "Isn't that much better?".