The Soul of Sevens is a third person cover up arcade style shooter game.
So after playing a while, the gameplay (and graphics) is not bad since it's basically like one of the usual cover up arcade shooters. Also you can manage and control other female characters which is nice. However the huge downside about this game is you have to pay in-game money (used for buying weapons/upgrading and gacha draws) to do a mission besides the stamina system. Here's a picture of it with circles highlighting the money requirement.
I pretty much doubt I'll be able to progress much since the missions (and along the daily logins) only give some money back. Or in other words, you barely make profit. Anyway, that is just plain dumb out of a lot of iOS games I played. Overall, decent arcade shooter style gameplay and terrible money progression.
Conclusion: Decent arcade shooter style gameplay and terrible money progression.
Note: Available in the Japanese app store.