The 8th son? Are you kidding me? Season 1 Episode 2

Wendelin decides to keep his magic a secret after learning it moves him ahead of Kurt in the line of family inheritance, risking assassination attempts from Kurt. Alfred discovers Wendelin has an extraordinarily high magic capacity. Alfred displays several unusual symptoms, cold skin, no sense of taste and bouts of physical pain. Wendelin’s strange behaviour draws Kurt’s attention. Wendelin decides he wants to be an adventurer instead of a lord, making Kurt less suspicious, but Adventurers Academy is expensive, so Wendelin decides to work to pay his own tuition. To help with travelling Alfred teaches Wendelin flight magic. Wendelin’s father hears a rumour of a Whispering Dead nearby, a sentient corpse doomed to become a mindless zombie. Wendelin realises he means Alfred and confronts him. Alfred admits he is dead but came back as a Whispering Dead to pass on his knowledge to an apprentice.