Although Metal Gear Solid: Portable Ops (MPO) and Metal Gear Rising: Revengeance (MGR) are considered to be canon by Kojima Productions[6][7][8][9][5][10][11][12] and Kojima,[13] they were omitted from some official timelines during the 2010s,[14], with the summary of one for Peace Walker describing Metal Gear ZEKE as the "world's first Metal Gear,"[15] while still alluding to events from MPO[16], and reproducing a 2007 document that mentions the game itself as part of the chronology.[17]