Cool... I've been looking at stuff.
Maya/Veil/Gabriel showed me her 'application' for Gabriel, so I thought I'd write down a little bit about how I see Eli.
I can see Eli slouched in a subway tunnel, ragged and unseen, playing a tiny pipe with a melody that halts and flows, jumps and starts, untrackable but with an underlying melody that captures the attention, taps the waiting foot or unsuspecting finger. His eyes are just brown when someone meets them, and, as all Mercurians, very plain and solid looking, but with a grin that's just on this side of dangerous. I could see him also taking a number of other guises, all very plain, all very much a part of humanity as it is, not as it wishes it were.
He's the mad creator, making, thinking, fitting pieces together that don't quite fit in order to find another, unseen Pattern that hasn't ever been seen before. Always shifting, fitting, seeing, measuring, and sometimes testing his creations unto destruction, just to see if they're up to the challange. Creator and destructor. He's also an engineer in that he takes the route that's outside the box. Does it the most creative way rather than the most straightforward. Makes people's minds shift when they look at a problem or soemthing that's familiar and makes it all strange, different. That'll be the hardest part about playing him, always creating another way of looking at what is there... and then shoving his minions into the mix. I'll probably have to work pretty hard with other folks to get plots where his machinations have the right mix of incomprehensibility from the players' point of view, but still fit in the full scheme of things.
Just as he can see how things would go together, he can also see how to take them apart.
Thing is that bringing a life into the world also means bringing another death into it. I kinda see this as the core of Eli's madness. All of his creations get destroyed, too. By time, entropy, or the curse of death from the choice of Mankind to eat of the flesh of the Tree of Knowledge. He's tired of all the destruction of all the the Good things he brought into being on the instruction and command of God.
I also kinda see that the reason Eli let everyone go is because he knows that creation is most easily done unreined, without rules, without guidelines, without any kind of form, completely free of restraint or someone looking over their shoulder. Have fun. Do it.
Hope that gives you a better idea as to how I'd see Eli.