A story about me, with physical strength E and magic EX, becoming the strongest while being lovey-dovey with my younger sister and maid.

Myria, too frail to leave her house, is summoned to the government office one day to have her status measured in a census. Though Myria worries she might die on the way, she is taken there by her younger sister Aria—an extremely capable adventurer, an extreme siscon, and an extremely beautiful girl—and there it is revealed that her magical ability value is EX, the strongest in the world―――