Our main character, Asai Manatsu, is the nice guy, who gets isekaid after he got dumped while proposing. Then he dies while trying to save a mysterious girl, but then wakes up in her body?!

Bullshit aside, this is just Dark Souls with waifus.

Short manga volumes that were bundled with disc releases of anime adaptation. Each focuses on one of heroines.

The Biblia Academy's Headmaster has asked to a Trinity Seven Kazama Levi, looking for the mythic weapon "Murasame", the legendary demonic sword. Along with Charme (Big Boobs), a kouhai mage that admires to Levi, she will infiltrate to a town where is said "Murasame" is sealed, however a Breakdown Phenomenon occurs----- Aiming to that treasure Lugh appears, who is the same "Envy" mage, also going to war, the leader of the Ninja Army's Five Shadow Magic Elements, Kashin Ryuhime, the story of a ninja having a heroic battleッス!!

Kasuga Arata lived a normal life in a small town, together with childhood friend and his cousin, Hijiri Kasuga. However, everything changed on the day of the Black Sun. The Breakdown Phenomenon which ruined the town where he took Hijiri away and resides was caused by the Black Sun. As Hijiri begins evaporating, she hangs a grimoire to his neck, requesting it to protect Kasuga. On losing all of his other friends as well as family and Hijiri distressed, Kasuga asks for his planet to be great again, which contributes to the grimoire artificially re-building his regular life, and making him forget the destruction of the town and Hijiri's disappearance. Lilith Asami, a mage, is sent to investigate the ruins and she finds the powerful spell within their stead. She makes Kasuga recall the specific events and hence the enchantment is broken, not without the grimoire telling him that Hijiri is not dead. Kasuga decides that his only alternative will be to become a magus himself therefore Hijiri could be rescued by him and he therefore joins a secret school for mages that copes with magic dilemmas all over the world, the Royal Biblia Academy. There he is introduced together with the Trinity Seven, seven powerful female mages who are at the top of the respective disciplines (Lilith being one of them) who will aid him in his aim to become a strong wizard and discover the truth about Hijiri along with the Black Sun. He soon discovers that another of the Trinity Seven, Arin, looks almost exactly like his lost cousin although she shows a wholly different character.

Everyday is a normal day in the small town where Kasuga Arata lives. However, everything changed on the day of the Black Sun, and following it, a magician appears before him. The Black Sun caused the Breakdown Phenomenon which destroyed the town where he lives. Because of this, his normal life was artificially reconstructed by a Grimoire that his childhood friend had left. Just what is the purpose of the magician coming to the town? What will he do with the Grimoire's keepsake?

From MangaHelpers:
Hana, a high-schooler that is known as the cutest girl in school, gets pulled into a supernatural event while on a beach trip with her friends. This event, called a "Red Night Eve" involves a transformed extremely massive shark, which targets Hana while she's swimming! Luckily, she's rescued by the siblings Yayako and Yuuto Kagimori, students from her school who know all about these occurrences, and who even have a support program AI named Acacia in their tablet to help them. Not long after, Hana and the siblings are involved in another event, this time involving her precious class pet parakeet being transformed into something monstrous. With all these supernatural events, Hana's life is never going to be the same.