You would have to apply to a GM to have your character removed, and it\'s only currently done rarely (if at all) from what I understand.
Unfortunately, I\'m afraid, unless you have compelling arguments, you may be out of luck. But take heart, from what I hear, due to early-in bugs, at some point, the database will be wiped, and you can start again. So all is not lost!
I concur, sometimes it\'s irritating to only have four chars available, but I believe this was done in order to prevent ueber characters from trying to have multiple chars, each of which is optimized for a specific purpose. It also reduces database and server load, as each of the characters is loaded (temporarily) on login. My advice? next time, don\'t create characters you don\'t intend to use, or ask around to see what characters would fit with what you want.
Though a guest account would be nice, that brings up its own caveats. (mostly anonymous profanity and spamming)
Edit And out of curiousity, what do you mean \'the only way into the game\'? Are some of your characters stuck in walls, etc? if so , use /spawn to free them. If it\'s a question of not *wanting* to play the characters, or being banned, then I have far less sympathy. But I doubt that\'s the case, all in all.