Gaining a new ability isn't always fun and games. In fact, many anime characters awaken their true potential through truly horrifying means. Some gain a new ability when pushed to dangerous extremes that leave them with no choice but to power up or pass away, while others create chaos with terrifying abilities that they have no idea how to control.
Anime characters who went through traumatic power awakenings include Goku of Dragon Ball Z, who went Super Saiyan after Frieza eliminated his friend and threatened his son. There's also Escanor of The Seven Deadly Sins, whose strange abilities led him to accidentally injure his brother, only to be wholly rejected by his entire community afterward. Meanwhile, Ayumi Otosaka of Charlotte perished the moment her power was activated.
No matter how these characters came into their power, they endured some serious trauma. Vote up the ones whose stories you find the most compelling.
There's not a lot in the world of anime that's worse than what Eren when through when his Titan-shifting abilities made themselves known. He'd lost two of his limbs and was in the process of being swallowed by a Titan - a sequence that made some first time viewers think that Eren had kicked the bucket. But he survives thanks to his ability to transform into a gigantic, man-eating monster himself. Further developments, including his Coordinate ability, would emerge under similarly miserable circumstances.
The Uchiha clan's eye-based ability is literally fueled by trauma. To awaken the sharingan, a person has to be in significant peril - and to awaken the mangekyo, they need to experience severe trauma.
There are countless examples of this throughout the family's history, but one of the most gripping involves Obito Uchiha. Obito's life was already pretty nightmarish before his mangekyo awakened - half of his body had been crushed in a landslide and he was recovering in an underground cavern under the supervision of his not-especially-nice ancestor, Madara.
In order to trigger his young relatives' latent powers, Madara seals a tailed beast into the body of Rin, Obito's former teammate. In order to stop the beast from wreaking havoc, Kakashi is forced to take Rin's life. Witnessing what appears to be one of his best friends callously taking out another friend is so upsetting for Obito that he awakens his mangekyo - and warms toward Madara's bleak vision of the world.
While Shinichi Izumi's powers actually took some significant time to awaken, the circumstances under which they did are among the most traumatic ones on this list.
Shinichi is still getting used to hosting the parasitic Migi when he's forced to fight his own mother, who has also been infected by a parasite. Unlike Shinichi, who retains his own consciousness, his mother is fully controlled by her parasite. This means that while Shinichi retains his bond with her, she takes no issue with slicing him to ribbons.
Both because his human body hasn't adapted to battle, and because of his emotional pain, he loses the fight with a blade through the torso.
Migi gets to work repairing the wound and reconfiguring Shinichi's cells to make him significantly stronger than he ever was - leading to a delayed power awakening when he finally wakes up.
Escanor's power, Sunshine, means that during the day, he's significantly stronger, larger, and more arrogant, while at night he's frail, weak, and submissive. Because he wasn't used to these dramatic shifts, he was unable to control his powers when they first manifested. He accidentally broke his brother's arm, and was subsequently disowned by his parents and was set to be executed by the Kingdom. Escanor only survived because a woman named Rosa put him in a barrel, which she set out to sea - and after that, he was perpetually reviled as a monster.