Born in the Grand Line as the family's first son, Dante was a kind and patient child with a hopeful future. Remarkably intelligent and studious for his age, he was always devoted to reading books and studying new things as they were his favorite thing in the world until his younger sister Echo was born, and she became his biggest treasure. Dante loves her dearly and always strived to be a good older brother and make his parents proud at the same time, but when his hometown was destroyed in a conflict between pirates and the Marines, the young Dante desperately tried to rescue his wounded parents from under the rubble only to watch them both die in front of his eyes. Without having time to mourn he rushed to rescue his crying sister who was buried beneath the debris as well, and rushed to escape the burning town with her. Since that dreadful day Dante promised he'd do everything in his power to keep Echo safe and alive, not letting anything hurt her since he never wanted to lose another loved one due to not being strong enough. At age 5 he started living on the streets with her and survived through stealing food, always making sure Echo had more than him and that she'd never feel cold and alone as they wandered from town to town, being called the 'trouble brothers'.

Always determined to become strong Dante trained himself and Echo on how to fight and survive whichever adversities came their way, only trusting his sister in the whole world. After many struggles Dante came upon a strange fruit in the wilderness while searching for shelter and food, recognizing it as a misterious Devil Fruit from many books he had read in his earlier years; aware that eating it would bestow him with powers that could benefit him and make him stronger to protect Echo better from any danger, Dante decided to eat it. He discovered it to be a rare Mythical Zoan type, and trained his newly obtained form to harness its power in order to keep his young sister and himself away from harm. However much to his dismay Echo also got ahold of a Devil Fruit not too long afterwards and undoubtedly she ate it as well, earning herself new powers too. Focused in keeping eachother alive Dante continued striving to survive whatever challenge appeared before them until he was faced with Echo's decision to become a pirate; and even though he was against the idea due to the amount of risks and pirates being the reason for their hometown's destruction, he knew there was no way he could change his sister's mind, supporting her choice and aiding her to assemble a crew of her own and taking his role as her own navigator.

Echo's crew proved to be surprisingly reliable and headstrong which brought Dante some relief even though he remained in his position as her own personal guardian no matter the situation. In time the Crossbone Pirates became notorious in the Grand Line and well-known for being a sturdy and fearless crew, never backing down from a fight being led by the brave and young captain. Even though the life of piracy was not what Dante was expecting he came to be accustomed to it and enjoys life at sea, having plenty of new opportunities to increase his knowledge and remain close to Echo, always able to keep an eye on her and keep her safe from the dangers of the world. Danger however was what Dante felt coming when his sister met no one other than Eustass Kid, one of the Worst Generation; immediately wary of him Dante tried in vain to keep him away from Echo but what he saw was only the opposite, as both captains constantly butted heads against eachother whenever they'd meet and in the process started to become closer. Concerned for his sister's safety he always kept an eye on Kid being even more protective than usual whenever he was around Echo, despite noticing that the red-haired man seemed to have a strange and unfortunate interest in her.

It didn't take too long for Dante to understand what was unveiling in front of his eyes; Kid and Echo were growing increasingly fond of eachother and despite wishing for his sister's safety above anything else (seeing Kid as a bad influence and a danger to her), Dante also wanted her happiness; and he was aware that being with Kid would make her happy. So in the end Dante (reluctantly) proceeded to allow the pirate captain to get even closer to Echo and watched their relationship bloom into a partnership and a full-blown pirate alliance. Aware that her choice made her happy Dante remains at her side as her most loyal companion, giving up anything to continue keeping her safe and sound.