Also my tests show that it has at least a 10% attack bonus, my guess closer to 25%. Not sure how much yet. Been testing vs DC wardon beetles. On BST with 129 str, 74 dmg main hand 64 damage off hand, 687 attack and 8% damage boost from killer effect, and no gorget or belt. did about 1300-1600 damage with normal tp return.
Then changed to MNK, 137 str, 127 dex, 80 damage H2H base without fstr, 730 attack. Shijin does about 1100-1500 dmg on normal tp return. Shijin is supposed to have about a 10% attack bonus. Lots of variables, but IF fstr is capped on both axe and H2H they will both have 91 dmg on mainhand, and axe will have 81 on offhand, and axe is most likely still far from cap. When counting attack bonus you will end up with about 800 attack on shijin vs 687 on axe. Shijin also has slight ftp bonus over axe ws.
Yet with all of that which should put shijin way ahead of Ruinator, once you take into account the 8% damage boost on bst they do similar damage with those setups.
Edit: still needs more testing, didn't do all that many WS's but that's what I got there. and once I did put WS gear on BST and used ruinator did 2k-2.5k damage with normal tp return. Where the highest rampage I saw was 1.5k.