That's funny and interesting. In Korean, "Ay-go" is like saying "Oh Jeez", kind of, but a little worse. Like if someone just told you that you had to teach 4 more classes after you just got done teaching 6 and you were about to go home. not much you can do but say, "Ay-go".
Anyway, i like the name, Eigomon. I'm sure the Japanese students really like it. But I don't think it would work in Korea, at least not as a motivator for learning English. Can you imagine, "Oh Jeez Monsters". But it works well in Japanese.
BTW, i never knew what Pokemon meant either.
Thanks for leaving your old characters on eslHQ and good luck with your new characters!