Decimus was born upon a ship sailing across the vast waterways and seas of Uros with his family, who consisted of his mother, father, three siblings, and vast array of other relatives. They were, in essence, a travelling band of fishermen that spend their whole likes aboard ships and over the waters, with the rare visits to land being for repairs, produce and items they couldn't get from the seas, as well as clothing which consisted of very light, simple attire. Decimus, being born third of his three siblings (older than one of them) was named after a distant grandfather and was often considered very similar to him. It instilled him to try and be the best person he could, so he could honor his family properly. This was his life, from childhood all the way to his late teens (around 17)
During these times, on his eighteenth birthday his father gifted him with a small collection of supplies as well as ownership of his own vessel; a small boat called "The Shell" - a boat made of primarily spruce woods and with large blue sails. it functioned much more like other vessels they owned- that being houseboats that each had their own sleeping quarters and functions. He was ecstatic, and happily accepted the gift as it showed a progression from childhood to adulthood in their small community.

Life was good for them, with the family enjoying the seas as well as all the trials/tribulations that came along with it. Decimus proved to be a natural very quickly with steering and managing his own vessel, though he chose to remain more within the middle of their travel formations, enjoying the feeling of the breeze on his face and the singing of birds in his ears. One day, on the even of his 20th birthday his family's vessels were hit by a massive storm, with Decimus torn away and separated from the rest of his family lineage and swept away into the seas. He woke up in the fishnet of a completely different group, drenched and confused. They welcomed him in, offered drinks, and asked about his family and where he came from. He explained everything, said he was from a family of seafarers, as well as where they were on the sea before being washed up. The people had no idea who he spoke of, but offered to guide him to the first stretch of land they could find so Decimus could get his bearings and process what happened.
He agreed, and since then has been wandering and trying to figure out where to go and what to do about everything.