Actually, don't forget the town that was full of normal yomas, where Irene, Sophia, Noel, and Priscilla met, to start their hunt for Teresa to execute her.
Coul this town not have paid, and the Org sent a horde of normal yoma to wipe out the town. And after the normal yoma wiped out the town, they stayed there, pretending to be humans, waiting for real humans to come, to eat them.
I firmly believe that Teresa was speaking true, and we got the town as I explained above to prove it
Also, don't forget they had that normal yoma working for them even though it knew that it was going to eventually die to some trainee Claymore (though Clare made sure it died to her, hehe)
Also, don't forget that "spiderman" male AB too, that was working for the Org.
Also, in those pics of the continent and the dragons, in the one showing the battle, with all of those armored soldiers, dragons, and male Claymores/Awakeneds:
if you look at the lower right corner, two of the armored soldiers' faces are visable... and they look like the faces of normal yomas! (at least to me)
Rig's face too looked like a normal yomas.
Teresa doesn't lie, as she says she has no need to, except when it comes to what her real power level is, hehe.
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Keep reading Claymore and you'll come across ENVY from the FMA manga/anime-Brotherhood. Seriously... well, closely the same anyways... hehe.
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about the continent:
Miria has no way of knowing, except that there must be another landmass, as the Org came from somewhere, because they DID. The Org arrived on the island, they weren't always on the island.
Miria had to have been told about the continent from Rubel. Rubel also himself says he's a spy too for this "other side of Dragons".
The problem is, Rubel could be making all of this up, lying his A off...
(I personally think Rubel is lying about being a spy, and he's actually the REAL-TRUE LEADER of the Organization! As to whether there's really these Dragons or not, is also very questionable, but possible too. But, if there are this "other side of Dragons", they are Rubel's enemies, as he's the TRUE-REAL LEADER of the Org, hehe! If you seen Batman Begins movie, I feel Rubel is just like Raz 'al Ghoul, pretending to be a subordinate, when he's really the leader of the League of Shadows)
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if you're interested in my theory of Rubel, I can explain and support it in much much more detail, hehe.