I vote that Ace would take over easily.
Well, since I'm there, you should know that I have a personality adverse to leadership. I don't like taking on an authoritative role, and have poor communication ability. If I attempted it, I'd be dead in no time. Instead, I would support someone with a similar agenda that can be my figurehead. Given the options, I'm thinking Ace. I'd stay on Ace's good side by becoming his right hand man.
I've found that in working environments, it is human nature for people to relieve stress by complaining about another individuals work. In the absence of this individual, the group typically picks another "weakest link" to focus their anger and frustration. Proin hates us all already, so I think he'd be the perfect person to take on this role. This would be a delicate game, because I'd want Proin to be the one taking shit from everyone, but at the same time, I don't want them to drive Proin off because then people would select a new target.
As for Nikkoru, if I am Ace's right hand man, then I'd want him to be Ace's left. Nikkoru seems like he'd be unlikely to stage a coupe so long as he is included in the decision making. I think we could work together well to support the figurehead.
Not sure what to do with Vicious. I don't see us getting along, and he's much more problematic than Proin, so I might have to arrange a disappearance early on.
Edit: I'm surprised so many people think I'd be the first one killed. Has anyone considered that having a Biologist in your group might be useful? You might think again when you see some berries and want to know if you can eat them or if they'll kill you.
