[GeneralTekno]

I know that I've joked that given the writer did Gurren Lagann, that they'll kill off Gentarou and everyone else will then have to become Fourze.

Interesting theory though. Whatever the case, Kengo is probably the best candidate. Plus, he'd make sense as someone to target given he's essentially the field commander who does all the tactics/strategy.

After all, Libra is FAR more tactical in his choices of switchers than Ms "Hand a switch over to every pouty kid I see" Scorpion was. Plus, he has the shapechanging ability to disguise himself - 'twould be easy for him to sew discord and sway Kengo over to his side.