Flames to Ashes
BlueOqua
Izuku Midoriya has both of his parent's quirks. When Izuku has not shown traits of either by the age of 5, he was diagnosed "quirkless" by his doctor. When the already broken family faces another tragedy, Izuku disappears in broad daylight right next to his mother. Unbeknownst to his classmates, his new brothers and sisters, and his own mother, he was right under their noses the entire time.