#ghostd

Kind of long, and I didn't want it to get buried in the Skype chat, so posting it here.

Basically, I just had an idea about how exactly D2's 'battery' works and such and was wondering how you guys liked it

Ok, so this assumes that the portal accident did have an affect on D2 aside from outright killing him. Basically, it made his body dependent on ectoplasm for functioning in the same way it's dependent on air, food, etc. 

However, D2 can't make ectoplasm of his own - he's still a human, he just needs it to survive.

GhostD, however, can make ectoplasm, and does just by existing. Especially as his emotions/obsession develop and he gets stronger, his ghost core produces ectoplasm just by existing. It's not a huge amount, but it keeps D2's body functioning, and the sharp increase in ectoplasm production that comes when GhostD stops being Vlad's obsession and gets his own obsession kickstarts D2 back awake

This would kind of explain the battery effect, too - when GhostD's been in D2's body for a month, D2 has ectoplasm reserves, a buildup of the stuff that takes him a while to burn through and use. But when GhostD hasn't been in his body as long, there isn't as much ectoplasm there to begin with, and thus he burns through it quicker. It's like being put in an empty room with no food or water - if you go in with a full stomach and well hydrated, you'll last longer then if you go in malnourished and dehydrated.

D2 still needs food, water, and air, but none of them can replace ectoplasm, even when taken in excess. 

What this also means is that D2 could survive without GhostD if he could find some way of collecting and administering other ectoplasm - think of the Gun Dog AU, if you know of it. The problem is that doing so would be an enormous hassle and a huge time consumer. D2 needs a lot more ectoplasm than anyone thinks, and the time it would take to take it from the Ghost Zone, properly concentrate it and then administer it is basically all his time. Being possessed by GhostD is simply easier for everyone.

That said, once Masters finds out, he has a few emergency ectoplasm shots made, not enough for D2 to live with, but enough that Masters can present himself as someone with the power to help D2. He likely uses one of these when D2 passes out at the concert in order to wake him up and make him the offer, and gives D2 an extra shot as a sign of goodwill (and then Team Phantom can figure out what Vlad already has about D2's dependency on GhostD)