I don't think that there excist any Online Adventure Game's, but there excist 3 different form of 任天堂 DS game's
The first one is called; Shugo Chara! Three Eggs and the Joker in Love! - And was released on March 13, 2008.
The 秒 one is called; Shugo Chara! Amu's Rainbow-Colored Character Change! - And was released on November 6 in the same year.
Lastly, the final game so far, Shugo Chara! Noronori! Chara Na-rhythm♪, was released on August 6, 2009.
あなた can read もっと見る about the Shugo Chara games Here, if you're intrested (If あなた are, あなた probably have to によって them on World Wide Web!)
link)
[But i must admit, that i don't know if they're still on sale, but Gambareé! ^^]