Age of Aincrad is one of a large number of websites affected by a severe Cloudflare bug (lookup "Cloudbleed" for more details). As a result of this bug, critical data - in our case, mostly your login data - may have been leaked. We have no way to check for the exact details of what has or has not been leaked, as there is a certain randomness involved.
In order to ensure your account safety, please change your password as soon as possible. Enabling Two Factor Authorization is advisable.
If you use your login data for any other accounts, please make sure to change those passwords, too. If possible, use different passwords.
To check if another site you use has been affected by Cloudbleed, please refer to this.