"In genre fiction, the term parallels the usage in television; it is usually meant to indicate a substantial change in narrative viewpoint and activity from that (previous) storyline based around the activities of the series' principal protagonist(s) and so is a shift to that action and overall narrative thread of some other protagonist(s), which now becomes the central or main thread (storyline) of the new sub-series. The new protagonist generally appears first as a minor or supporting character in the main story line within a given milieu, and it is very common for the previous protagonist to have a supporting or cameo role, at the least as a historical mention, in the new sub-series."
so far as we know, none of the characters are in each other's games. But that could change at e3, we just don't know yet. Secondly, it seems that the world they are on is completely different.
ODST fits the description because it revolves around the events of halo canon, but with a different character. ffx-2 is a spinoff, as is the ff title starring vincent, but from the looks of things, ffV13 is in its own world and characters.
