Darkness Myth ~Igyou no Kamigami to Kyuu Shihaisha~

You lived an ordinary life.
One day, the city you live in is enveloped in flames and someone tries to kill you!
Just as you are cornered into a near death situation, the Elder Gods from the Cthulhu Mythos appear before you.
They tell you they want you to lend them your strength and go on a journey to seal the Elder God of Cosmic Evil—Cthugha.
You resolve yourself to go on this journey to seal Cthugha in order to save humanity and exact revenge for your parents’ murder.

[from Google Play]