The Archives are used to help the player figure out the story as they continue playing. They have been featured in all three games; in Forbidden SIren 2 and Siren: Blood Curse, the Archives were upgraded. The Archives in Forbidden Siren only has static objects, while Forbidden Soren 2 and Siren: Blood Curse feature other media such as audio and video files, and even interactive games..
Archives in different games
The Archive contains 100 entries that fill up as the player finds objects. Some Archive items are required to unlock secondary missions, or they are the secondary objective themselves. Once all entries have been unlocked, a secret movie is unlocked in the Link Navigator and a minigame called Zuno 頭脳 (Brain Cell Revival) becomes available.
Forbidden Siren 2
Again, the Archive contains 100 entries and again, full collection of the items grants a secret movie. Some of the Archive items now are audio and video media instead of just static pictures. After all the game archives are found, a secret stage is unlocked, being able to play as the shibito Nitaka Ichifuji.
There is a 101st hidden archive, as a real material (letter). Set written by Yuko Kifune, a former girlfriend of Soji Abe, it was only found in a book published in GAME JAPAN. It is no longer available since that book has been discontinued.
Siren: Blood Curse
The Archive here has only 50 entries, but still retains audio and visual entries from the second instalment. To compensate for the lesser amount of entries, weapons have now been categorized in an 'Archive' style so players may collect the weapons of the game in similar fashion to Archive items.