Nash is a young boy with short brown hair and purple eyes. He wears a moss green vest over a light purple, long-sleeved shirt and grey pants. He also wears brown shoes with light brown socks.
Nash is a stoic and calm child but possesses a rather bratty nature toward Asta, often being more critical of Asta due to his inability to use magic and his failure to have Sister Lily accept his proposals. Nash's criticism of Asta would often leave Nash teasing him most of the time and when Nash finds out that Asta is aspiring to become a Magic Knight and eventually the Magic Emperor, he continues to discourage Asta even more. Like all the other orphans in his village, Nash has displayed praise toward Yuno because of his talent in magic and accepts Yuno as far more capable of being a Magic Knight than Asta and seems to hold more encouragement for Yuno. In an anime-only episode, it is revealed that his discouraging behavior toward Asta is all due to the fact that he believes that poor commoners like themselves can't dream on bigger things but Asta's words of determination to never give up especially on dreams pushes Nash to take Asta's words more seriously and look at the possibility of things even though it is not likely to happen. When Asta and Yuno leave for the Magic Knights Entrance Exam, Nash's demeanor somewhat changes as he openly accepts that dreams can indeed come true, aspiring to be a Magic Knight someday.
Aside from his initial behavior, Nash truly does show that he cares for those close to him and would do anything to protect them if danger arises their way. This can be shown when he tries to protect Sister Lily from an attacking elf but Yuno and Asta end up saving them eventually, showing that Nash can be brave if it means protecting his loved ones. Despite his initial attitude toward Asta, it is noted he truly does care for Asta when he hugs him and says his goodbyes to Asta and Yuno and has since then been happy for Asta after he manages to become a Magic Knight.
One day, Nash teases Asta after Yuno interrupts Asta's series of proposals to Sister Lily. While lighting a fire to help Recca boil a pot of water, Nash reminds Asta of the differences between him and Yuno. The following March, many of the villagers gather to watch the Grimoire Acceptance Ceremony. Nash and the others from the orphanage are shocked when Asta does not receive one but Yuno receives a four-leaf clover. They then head back to the church for a feast.
Several months later, the villagers of Hage are left confused after the kingdom is saved from the Arrows of Judgment and the demon skeleton shines with light. They watch as a dungeon rises over the skeleton and passes overhead. A possessed Purple Orca then attacks the villagers. When the elf attacks Lily, Nash jumps in front of her, and the pair are saved by Yuno and Asta.
A few days later, Nash reads the newspaper article about Asta's trial.