achaea.comは安全ですか？

Bad business practices. Impolite customer support, low quality service, volunteers can access players' private information. Furthermore, the game favours paying customers to the point where you have no chance to succeed without investing large sums of money in the range of hundreds to thousands of dollars. This aspect of the game however is hidden from newer players under a nebulous term "credits". Although there is a possibility of buying credits through in-game means, you will always be at a disadvantage. I've played this game for two years and was defeated by a 2-day-old character, who simply bought the best weapons, armour and other gear (artifacts) through the cash shop. If you're looking for a MUD to play, I recommend picking any of the many other alternatives and staying as far away as possible from the IRE.

@Maya_Lysander However, volunteer users go through a reasonable amount of legal red tape, so they do have some accountability there. Payment for pay-for-props is secure. I've had no trouble with it at all. And for the overly-paranoid, they've more recently added a Paypal option.