Ore no Osananajimi ha Joshikousei de Isekai no Yuusha (Web Novel)

俺の幼馴染は女子高生で異世界の勇者なんだがそれだけじゃないっぽい
Romaji: Ore no Osananajimi ha Joshikousei de Isekai no Yuusha nandaga sore dake jyanaippoi.
Alternative Title: My Childhood Friend is a High-school Girl and a Brave in Another World but it looks like there's more to it.
Author: Yamatanaka Mikiya (山田中ミキヤ)
NCode: n3275CF

Quote:

After the closing ceremony of school term, Shimoyama Yuuki is told by his childhood friend, Sakurai Arina that she is a descendant of the Brave one. She has to travel to another world and asked Yuuki to join her, At first dismissing Arina as joking, he is quickly forced to believe Arina as she produce fire from her hand right in front of him. Even that, he still refused to accompany her but gradually agreed to, knowing Arina is a clumsy, shy, weak-willed childhood friend and Yuuki worried if she could accomplish on her own. After receiving a device from Arina's mother, they enter through a teleportation gate and arrived upon a village far from the supposed destination, furthermore they can't understand the language and penniless, will they be able to safely accomplish their quest!?

For those who are into Yandere!

Seems like translation is going out there~

Ore no Osananajimi ha Joshikousei de Isekai no Yuusha (Web Novel)