I can confirm that the characters are stored server side (I looked for hacks--testor first remember--there are none to the characters stored in the software downloads).
However, gui settings, preferences, logs, screenshots, and such are strored for each character (except w/ bugs) in the package of software on your user computer.
As long as there is a client accessible to you on a network, you can get to your account--unless you are currently logged in elsewhere.