I don't really like the idea of killing one Mr Frog (or otherwise writing one out of the story), as it kind of feels like a half-assed attempt at fixing my dumb idea to have him cloned in the first place (the way I look at it, the mess has already been made; might as well make the best of it). I do, however, rather like the idea of having the two Frogs develop in different ways. I don't see the two being all that different in terms of core values, though, at least to begin with. Spearbreakers!Frog would likely be less antisocial on account of being forced to work with the dwarves of Spearbreakers on a daily basis. Eris!Frog would probably be even more arrogant than before, seeing as how he played a large role in felling Joseph.
I seem to remember there being a Thing where it wasn't possible to teleport to any universe at will -- one is only capable of moving between nearby/related universes. Would it be plausible for Eris!Frog to have returned to Everoc, with Silena possibly in tow? The two would probably have the same goal of fighting the Spawn at that point, but they wouldn't meet up immediately -- I see Spearbreakers!Frog as becoming an advisor and weapons engineer for the larger dwarven society (thus explaining the fancy weaponry we get in the sequel), while Eris!Frog vampirises himself (by tracking down one of the few remaining vampires in Everoc) and starts his own independent faction.
@Terrahex:
A lot of things didn't get resolved due to various unfortunate occurrences, sadly. We'll just have to be very careful not to be specific about how certain plot threads concluded when referring to events that happened between SB1 and 2.
@Reudh:
Almost-certainly. Mr Frog's a clever sumbitch. He'd definitely work out a way to feed himself without having to take blood from a living creature eventually.
I'm not going to think of anything specific for my new character yet, save that their name will be Kero if male and Anura if female.
An idea I wanted to introduce before was the existence of a "Cult of Holistic". Not sure how it'd work save that it'd be matriarchal in nature.
E: For the record, I do plan on having one or both Mr Frogs take on an alias so as to ease the confusion.
E2: Random thought... we know souls exist in this universe. It's possible that the cloned Mr Frog literally does not have a soul. Not sure what that would do, though.