I like the idea, but don't you think that's good material for a bonus game instead of for one of the 5 'quintology games'? Each of the five will introduce a new creature, isn't that what they said? Or is it just a new hero (so it can be a known species)?
How would those native sligs look like? Maybe they eat special plants (who was it again who wanted squeek to be plant?) that work like some kind of drug, so they change in big , strong and powerful (and maybe even smart) sligs!
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