Secret characters are more common in fighting games, which are fundamentally based around a set of different characters. However, they can occur in any kind of game.
In some cases, secret characters are given as a reward for completing a game - a process usually described as unlocking a secret character. The Tekken games are a fine example of this, as they actually provide empty spaces on the Character Select screen for characters that have not yet been unlocked.
Other secret characters, however, are far more secretive, and can be classified as a kind of Easter egg. Some may require the player to accomplish impressive or unusual gameplay feats, and some can only be obtained by using cheats or hacks.
With regard, then, to State secrets, we remark that real statesmen do not endeavor to cover up their doings in the dark, and that the practices of diplomatists, and the reputation they have for duplicity, are not such as should encourage individuals or associations to endeavor to conceal their proceedings.
Neither does it follow that secret societies are charitable because their members, in case of sickness or death, are entitled to a certain portion of the funds which they themselves have contributed as initiation fees and quarterly dues, while those who are in real want can not even become members.
The pretentious character of secret associations appears, also, in their claims to be the possessors and disseminators of knowledge and morality.
A secretcharacter (not to be confused with an unseen character) is a playable character in a video game that can only be played by completing some task in the game.
Secretcharacters are more common in fighting games, which are fundamentally based around a set of different characters.
Ayane was a secretcharacter in the original Dead or Alive but is a main character in every subsequent installment of the series.