When creating BIOS EX – Yami No Wakusei The developers were inspired by the anime of the same name, adopting its best features. The plot talks about a character named Yeiz, who caused a terrorist attack, was detained. But when he comes to his senses in the cell, his mind is muddy. The guy remembers nothing but his own name and the fact that he is not a terrorist. But the government is of a different opinion, charges of what happened. Now, in order to get out of imprisonment and wash off the dirt on his own name, the hero needs to prove innocence using any tools available for this.

Like the projects of such a genre, in BIOS EX – Yami No Wakusei all the attention is focused precisely at the narrative. The story consists of more than 50 thousand words, where there are also 4 branches. In the end, they are intertwined, and depending on the circumstances can lead to unique endings. One of these circumstances will be relations with girls who will alternately be introduced into the plot. As Yeze communicates with them, their emotional state changes, displaying on facial expressions. At the same time, dialogs, like individual remarks are not voiced, but only displayed on the screen in a separate column. Instead, against the background there is a monotonous composition suitable for the pace of development of the plot. But if desired, a gamer can skip some fragments using the corresponding function.