Mechanical Girl, Total Annihilation

Adel, a Technician with the ability to "create objects from materials," was considered useless in combat and a burden to the most powerful party in the city of Isaac, "Golden Whirlwind."

One day, he is suddenly kicked out. In desperation, Adel receives a mysterious request from the family of Count Cartlett — who were murdered by thieves...

(From Spanish on mangadex via google translate)