Board Thread:Warhammer 40k General Discussion/@comment-46.162.84.254-20130704080553/@comment-71.218.157.149-20140714102225

Despite the idea that the Tyranids could have been traveling between galaxies for supposed "Millions of years" there's no official proof in the lore, We only think the Tyranids came from another galaxy since they did not emerge from the Milky way. For all we know the Tyranids came from a black hole in between the galaxies, from who knows where.

But in the case that the Tyranids have been traveling galaxies for millions of years to feed their race, it's likely that the amount of Tyranids that there are now are on such a grandeur scale that they are attacking multiple galaxies at once. Similar to what Dyrcaend said, I doubt there will be some massive Tyranid horde numbering in the quadrillions decending upon the Milky Way galaxy. There's probably not many untouched planets ripe and ready with biomass in the Milky Way galaxy after 10,000 or more years of near eternal war. If the Milky Way Galaxy was as it were during the Dark Age of Technology, then there would be many more Tyranids coming for the biomass.

And if the rest of the Tyranids were coming to the Milky Way galaxy, which according to Callum would arrive in M51. By that time I'm sure the wars in the Milky way galaxy and combined the continued rising of the Necrons would have destroyed almost all biomass in the galaxy, the Tyranids would have simply wasted time ;) and of course the hive fleets would begin fighting over the scraps of biomass left in the Milky Way, the Tyranids might be forced to learn how to grave rob.