Senki Survival Saga: Isekai no Unmei wo Kaketa Mujintou Fujun Iseikouyuu

Anastasia, an elf said to be the most powerful magical talent in a thousand years, is fighting in the final battle of a three-way war. In the midst of battle with her arch-enemies, the demons, Anastasia finds herself enveloped in an intense light, and wakes up on a deserted island in another world. As Anastasia explores the island, she meets a mysterious stranger, and what's more, she finds herself unable to use magic…! This is a survival comedy about a beautiful elf girl from another world, stranded on a deserted island with an ordinary man!

(Source: ComicWalker, translated)