from Record of Ragnarok
Kojiro Sasaki is a famous swordsman from Japan, known as "History's Greatest Loser". He is the winner of the third round of Ragnarök and the first human to kill a god, Poseidon, the most fearsome god of all, by cutting him into pieces. Kojiro used the third round as a chance to evolve his swordsmanship even further and succeeded. In his youth Kojiro acted in a carefree way, he often arrived late for training in the Toda Dojo and would laugh about most things his masters said. When he was in the middle of combat he took it seriously until he realized he couldn't win, then he would just surrender and laugh about it. However, Kojiro really put a lot of effort in his training, he wouldn't stop until he overcame the one who defeated him before, but he didn't care about being recognized as "stronger", so he never pled for a rematch. His only regret when he was alive was that he wished he could fight more.

Record of Ragnarok
High above the realm of man, the gods of the world have convened to decide on a single matter: the continued existence of mankind. Under the head of Zeus, the deities of Ancient Greece, Norse mythology, and Hinduism, among others, call assembly every one thousand years to decide the fate of humanity. Because of their unrelenting abuse toward each other and the planet, this time the gods vote unanimously in favor of ending the human race. But before the mandate passes, Brunhild, one of the 13 demigod Valkyries, puts forth an alternate proposal: rather than anticlimactically annihilating mankind, why not give them a fighting chance and enact Ragnarök, a one-on-one showdown between man and god? Spurred on by the audacity of the challenge, the divine council quickly accepts, fully confident that this contest will display the utter might of the gods. To stand a chance against the mighty heavens, Brunhild will need to assemble history's greatest individuals, otherwise the death knell will surely be sounded for mankind.

Record of Ragnarok (Manga)
High above the realm of man, the gods of the world have convened to decide on a single matter: the continued existence of mankind. Under the head of Zeus, the deities of Ancient Greece, Norse mythology, and Hinduism, among others, call assembly every one thousand years to decide the fate of humanity. Because of their unrelenting abuse toward each other and the planet, this time the gods vote unanimously in favor of ending the human race. But before the mandate passes, Brunhild, one of the 13 demigod Valkyries, puts forth an alternate proposal: rather than anticlimactically annihilating mankind, why not give them a fighting chance and enact Ragnarök, a one-on-one showdown between man and god? Spurred on by the audacity of the challenge, the divine council quickly accepts, fully confident that this contest will display the utter might of the gods. To stand a chance against the mighty heavens, Brunhild will need to assemble history's greatest individuals, otherwise the death knell will surely be sounded for mankind.