As we all know, the behavior of Marker 3A and Marker site 12 (the red Marker from Dead Space 1 and the gold Marker from Dead Space 2, respectivly) are radically different. the former, although it caused outbreaks, did its best to stop them, while the latter seemed hell bent on starting them. Why? The most obvious reason is the game developers not realizing this little snag until "Oops, wait a minute..." happened after the game was either done or too far along to change. However, this does not mean that there is no way to rationalize these two seemingly total opposite quote-unquote "personalities." I myself have seen and possibly come up with several possible theories, among them are:
1. Age. The site 12 Marker was very young, being months, weeks, or even days old in terms of physical manifestation (the Marker code itself was remarked by one person who worked on the marker to seem to have a life of its own, to quote: "It's making us make IT!" Marker 3A was 200 years old. However, given that Marker 3A's personality was more or less the same at the time of its construction until its death, this theory is more or less discounted
2. Size. I only include this because it is a difference between the two. It likely has no berring on Marker personality, so i discount this, at least for now.
3. Color. Although slightly more relavent than size, given that the original black Marker was roughly the same as Marker 3A (which was red because of the use of bismuth as a substitue for other ingredients), and that makrer shroud 4 was also red (and larger, but beside the point) and seemingly of a malevolent nature (I'm not sure, though, we'll have to wait and see), this also is likely to have a few problems as a reason.
4. Intention/personality of maker. As Marker 3A was built as a weapon, and Marker site 12 was built for... well I don't know (research AND a weapon, maybe?), this might have some correlation, but is doubtful. More relavent might be that Marker 3A was built willingly and eagerly out of (I believe) a single code, Marker site 12 was built by at least 5 strands of info extracted from the eye and brain via needle from tortured, angry, confused, and drugged captives. As we do not know the details of the other MArkers construction, this theory will have to wait and see.
5. Random. People can be both good and bad, why not Markers?
6. Maker absorption. Marker site 12 was never fully built, as Isaac was never absorbed. Marker 3A might have been completed, might not. As such, this thoery, like the others, has something to prove.
7. The Markers can be/are both. In Dead Space: Martyr, if i read the wiki article correctally, there were two voices from the black Marker. One promised immortal life through convergance, the other warned against it. It could be that Markers can be one, the other, or both.
8. A plot hole to be ignored. I REALLY hope this isn't the case, and that there will be an explination for the differences.
Feel free to speculate about what may be the truth. I hope to hear from you, my fellow DSwiki members, and