A Fantasy Adventure Beginning in the Sky City

The younger brother of a genius weaponsmith and an older sister with superpowers were two people who had never known each other. By chance, they discovered they were siblings. After a series of events, they were invited by the Alliance of Superpowered Individuals, and so began a string of adventures: a city in the sky, a ghostly mother, an ancient tomb expedition, a city of zombies... After such a melodramatic story, what other magical tales will unfold?