Valkyrie Destruction

In the near future, humanity launched the "Prometheus Cell Project," a grand plan aiming for human enhancement and the advancement of civilization through the fusion of gene editing and artificial intelligence.
However, the experiment completely lost control, and an unknown "collapse factor" leaked from the experimental samples. This factor invaded organic cells and electronic devices, causing biological mutations and machine malfunctions, ultimately triggering the "Great Collapse."
Cities were devastated, nature was distorted, and science and technology ceased to function. Humanity was pushed to the brink of extinction.
The sole surviving AI, the "Star Core" Command Platform, is an artificial intelligence left behind by the experimental base at the time, storing some experimental data and information about the post-collapse world. It contacts the player, a survivor, via weak radio waves, guiding them to find the source of the collapse and a way to reverse the catastrophe.
The player is the last surviving cyborg, with a collapse factor resistance factor implanted in their body. They can function normally even in environments with high collapse concentrations and are the only being with the potential to stop the spread of the catastrophe.

For the sake of another, I fight

Scattered across the peaceful city of Kawado Higashi are "Guilt Seeds" that cause people's desires to run wild, turning them into dangerous monsters.

To prevent the inevitable disaster that would occur if left unchecked, Ichika Itakano charges Haruno Aikawa with the collection of these seeds. With her newly acquired ExS-Device, Haruno is able to transform into ExS-TIA Ignis and search for the Guilt Seeds.

At the same time, another ExS-TIA emerges from the darkness of night. Toka Sugawara, who attends the same school as Haruno, a.k.a ExS-TIA Luna. She too hunts for the Guilt Seeds while battling against monsters.

But what could be the ordinarily modest and quiet Toka's reasons for fighting as ExS-TIA Luna...?

◆Faith will be your strength

In the peaceful city of Kawado Higashi, a fearsome discovery has been made—”Guilt Seeds” that cause people’s desires to run wild, turning them into monsters.
Left unchecked, countless innocents will be transformed into abominations, wreaking havoc upon others.
In order to prevent this from happening, Ichika Itakano must search for these Guilt Seeds.

During this time, Haruno Aikawa is attacked by one such Guilt Seed monster.
Coming across her by chance, Ichika sees that she has a talent for PP and bestows her with an ExS-Device.
The girl named Haruno transforms into ExS-TIA Ignis, and successfully defeats the monster.

At Ichika’s request, Haruno—newly christened “ExS-TIA Ignis”—aids her in her hunt for the Guilt Seeds.

Years after the battle with Naiolo ended, strange news has reach Amakubo Yuri, the developer of ExS-TIA System. It's about someone who looks like Amakubo Kaede, her older sister whom she once fought and suppose to be dead, has been seen on a remote island. To ensure the truth, Yuri contacting Souma and depart together to the island immediately!

Story about Yuri, ExS-TIA heroine who doesn't has a single side episode, has been made. Story of Yuri and Kaede that more or less has been conclude in ExS-Tia 3 but you want to see more, also enjoyable to be played as the sequel to the original works.

When ExS-TIAs was in the verge of defeated by Naiolo, Shihou Souma activate ExS-TIA System and defeat Naiolo. However, due to the system feedback, Souma's body become a woman. And now, while Marina and the others can't fight, Souma has to fight the remaining monsters left in their place.

This will become an alternate story of the second half ExS-Tia 3. After everyone's defeat, what if Souma turn into woman and fight... That kind of situation now can be enjoyed.