IF the krids were created by Moagim: they are serious geezers, being trapped in the Tain that whole time. Of course, we've seen in Myth TFL that time plays weird tricks on people trapped in there ("2 days for us, a split second for SB...," or something like that). Do you think that they invented any games to pass the time, maybe Russian roulette to figure out which of them they'd eat next? Seriously, though, I don't think it's possible that there were a finite number of krids--IF (and it's a big if, seeing as how none of us actually crafted this story) the basic requirement for a krid to grow into a giant is that it gets old, one would think that all of the krids still living were on the verge of doing just that. I assume that Moagim would have created all of them in relatively the same amount of time, which means that if they were alive for a millenia or two in the Tain, they would all have to be of approximately the same age, and so we should see a lot more giant krids than the scattering found in the game. Plus, if two or three warriors are capable of bringing down a fully healthy krid, I doubt that they have the magical cajones for such a long lifespan. Only the giants die in a strange way, reminiscent of the Trow or Forest Giants. I think that that's more a mark of their power than anything else--I mean, the remains don't disappear or anything, they're just a pile of black stuff that the warriors wipe off their swords after the battle. I mean, really, if Moagim had such unbelievable power, would even Connact be able to stop him? Couldn't Moagim dream a couple thousand krids behind enemy lines and have them decimate his forces? No, I think that they must have come from somewhere, and that no matter how disgusting it sounds they must be able to procreate. Maybe a better question to ask is why Connacht didn't just wipe them out when he had the chance, rather than imprison them. Was he even then showing the signs of corruption? Not to mention the fact that he would have to unleash a spell of inconceivable power were he to attempt to con-Tain the same number of krids in the Tain as those encountered in Myth 2. Now I'm going off on a tangent. The point is, I don't think Moagim had the power, nor do I believe that the facts in the case support the claim that he created the krids by an act of sorcery. Of course, maybe he just happened to find a big, ugly female ghol and...
I'll leave that to your imagination.