Hikage Shinomori was a former Pro Hero and the fourth user of the Quirk; One For All.
Hikage was a valiant and noble hero was determined to defeat All For One. However, he was well aware of his limits and understood he couldn't defeat All For One by himself, so he spent his life training and strengthening One For All to be passed onto the next user. Hikage was descibed by Daigoro Banjo as a "weirdo" who preferred to spend his time in solitude. It was implied that this was due to his Quirk constantly putting him on high alert.
History (My Hero Academia Series)
At twenty-two, Hikage was entrusted with One For All by the third user at some point in the past. However, understanding the wide gap in power between himself and All For One, he chose to spend his time on the run and training to strengthen One For All to be passed onto the next user. Eighteen years after inheriting One For All, however, however, his body started to break down, due to his body not being able to handle the stockpile of multiple Quirks. It was around this time that he passed One For All onto his successor, Daigoro, before dying of "old age".
Powers and Abilities
Danger Sense: Hikage's Quirk allowed him to sense incoming threats in the surrounding area, giving him ample oppurtunity to react to them. According to Izuku, once a threat is detected, a stabbing sensation is sent to the user's head.
One For All: Transferred to him from the third user, Hikage's second Quirk allowed him to stockpile an enormous amount of raw power, allowing him to significantly enhance all of his physical abilities to a human level. This resulted in unbelievable levels of strength, speed, agility, and durability.