Let's see... Sigma will probably be too overwhelmed to speak out.
Backer, on the other hand, will probably be the only one who came to the End of Time of his own will, and coupled with the knowledge he'll glean from the Frozen Flame, he won't need to ask much besides "What do you need me to do?" He might also be interested in learning what exactly ZEAL's done that justifies his action.
A little elaboration on Backer's origins: He's something of a non-entity who wasn't supposed to exist in this dimension. Originally, his body was supposed to die in that experiment. However, a deity-like being (think an alternate dimension's FATE) intervened and exploited the circumstances to sculp a hero (explaining why his psyche seems computer-like). I plan to continue his story after this fic and reveal more, but that's about all that'll come into play in this fic. One possible extension of this could be Gaspar not expecting him to arrive (I'm not sure exactly how Gaspar's looking for heroes, but he might inconveniently miss Backer, who fortunately turns up on his own.). Or, maybe Gaspar noticed him, but didn't summon him as he would turn up on his own (bringing along Hunter and Amy).
Anyway, I plan to cover up through his arrival at the End of Time in my next scene.