Just finished reading DS:Catalyst, and a couple of things need to be brought to this wiki from the information gleaned from the novel. First and foremost, is the state of Markers in the Universe.
Let's start with a recap. If you've played DS1, you know of the Aegis VII Red Marker, once called 'Marker 3A' in a Military Log. We also know of the original Black Marker on Earth, and the story surrounding it from DS:Martyr. Finally, we have the McGuffin of DS2, the Site 12 Marker/Isaac's Marker.
After reading Catalyst, two things become aparent.
1: Markers, if there are multiple in the universe, will comune with each other, indicated on page 195, when Dr Dexter indicates the Aspera Marker (Which I'll refer to as 'Marker 4A') is communing with Marker 3A on Aegis VII, and a supposed secret Marker (Marker 2A) on Kreemar, via it's pulse's. Interestingly, none of these Markers are directing their pulse's back to Earth, to the Black Marker (Marker 1A). This may be explained by the next point.
2: The Marker's, espetially Marker 4A, is obsessed with 'reproducing', and sending the data of it's construction out into the universe. Sometimes described as 'growing a garden', this forcefull reproduction comes at the cost of certain people's sanity, e.g. Jensi, Ensign Haley, Istvan. These people have 'different brains', and are able to interperet the pulse's the Marker sends out, and are able to transcribe and translate the information into construction plans for new Markers. We have seen this before with Marker 1A, with Altman becoming the vessel of the Red Marker codes, and Isaac + Strauss were used by M3A to create the various Markers of Site 12, notably M12A (Isaac's Marker). However, notice that M1A, in Martyr, fell silent once Altman sent it's code back to it. The pulse's stopped, as the seed of the next generation of Markers had been passed on.
That final fact makes me curious. Did Jensi, who is implied to have killed himself in a fit of Dementia on the final pages of Catalyst, do so because M4A didn't need him to carry the seed anymore? Did this Marker realise Ensign Haley, in orbit above it, was carrying it's seed, and planned to spread it further than Jensi could? Is Haley the 'Gardener' of Generation two of the Markers, creating Marker 5 - Marker 11? Or even more? And did this stop M4A's pulse's?
One final question; why wasn't M12A attempting to plant it's seeds further? Why did this marker activate a Convergance event, when the others haven't exhibited an event even when surrounded by Necromorphs? Does a marker require the 'Maker' of it, the 'Gardener', to come and complete the Convergance process, as implied in DS2.
We may have to wait and see.