This is the ability to play as different characters each time through the game. For example, the game "Diablo" allows the player to choose one of three character classes: warrior, rogue, or sorcerer. Party-based RPGs can have a good degree of replayability, even if the plot is essentially linear. The plot of the first Final Fantasy game remained the same with each play through, but since the player was able to choose their party of four from six different classes they could choose a new party configuration with each new game. The "Final Fantasy" instruction manual even gave the player ideas for different types of parties (well-balanced, heavy magic use, combat oriented characters, etc.). In the first "Final Fantasy" game you can choose from the classes of Fighter, Thief, White Mage, Black Mage, Monk, and Red Mage, providing the player with 15 possible character combinations with 4 distinct classes, or 126 with repetition. Multitude of classes, accompanied by a multitude of races, is another typical characteristic of "roguelike games". For example, "Dungeon Crawl" at this moment employs 22 races and 23 classes, allowing a total of 654 race/class combinations (although about a dozen of them are disallowed due to in-game race/religion constraints). Typically, some races are more suited for some classes, and much less suited towards others (an ogre usually makes a great fighter, but a very lousy wizard). Such "unsuited" combinations may prove an extra challenge for an experienced player, yet it's not frequent for this challenge to be high to the point of the game being unwinnable. In some RPGs, such as "Skies of Arcadia", the player controls the leader of a party of characters, and additional members will join the group if the player makes the right decisions. It is unlikely that a player will "collect" every possible member on their first attempt, so they may choose to play through the story again in order to acquire the full cast. Different characters offer new ways to tackle the obstacles within the game. They may also offer unique dialogue options and opportunities to interact with other players. SquareSoft (now Square Enix) RPG Chrono Cross was an example of this with over 40 characters available for play. In the case of action-oriented games, there may be some areas in the game that are only reachable using a character with certain abilities. For example, see the Sega game "Sonic & Knuckles". The character Knuckles can explore areas in "Sonic the Hedgehog 2" that the previous characters couldn't.