Senki Survival Saga: Isekai no Unmei wo Kaketa Mujintou Fujun Isei Kouyuu

Anastasia, an elf renowned as a once-in-a-millennium magical talent, faces the final battle of a three-way war in another world. In the midst of battle with her arch enemies, the demon race, Anastasia is enveloped in an intense light and, when she awakens, finds herself on an uninhabited island. As Anastasia strolls around the island, a mysterious human appears before her, but she can no longer use magic...!? A survival comedy featuring the most powerful and beautiful girls from another world and an old man washed ashore on an uninhabited island! (Source: Kadokawa, translated)