OH MAN...... This is a fun question to chew on!!

He only had one that he knew, which was his grandfather! Due to the complete lack of knowledge about his parents or any other family beyond that they're all dead, and his last name ("fyst" was a family name used for soldiers), I imagine that there's some story there that he was never privy to. A mystery he'd never know the full story for; all he knew was that he had his grandfather.

(For what it's worth, I imagine his grandfather was well aware of what had happened to Ardbert's parents and the rest of the extended family, but the boy was young and never knew his parents and didn't need to be burdened with all that.)

In my HC his relationship with his grandfather was good! Good, but not extremely close; his grandpa did his best with suddenly having a tiny child to take care of, but he was old and gruff and a ranching man with a soldier's history. Well meaning, loving in his own way, but not one to say it out loud. A case of Ardbert loving his grandfather more than he knew his grandfather loved him; not unusual for him, but definitely something that would go on to influence his inability to read other's feelings about him in the future.

On top of that, his grandfather had just lost his child, and was facing the strange heartbreak of now caring for the grandchild he had been so proud of his own child for having. For an already emotionally reserved man, this meant withdrawing even more from expressing how he felt about the child.

Thus, his view of Ardbert was as a child who deserved a better world than the one he himself was currently struggling to come to terms with. This meant finding him a teacher and raising him on gentler things; stories and Amaro care, and a hands-off sort of almost fear of intervening. Ardbert knew and loved his grandfather as his beloved and only family, but his grandfather was Security and Home as much as he was a person, someone he could scramble back to after scraping his knees as a tot or hang on to the sleeve of while learning how to avoid the hand-severing bite of otherwise placid amaro. He knew the security maybe more than the man.

That all said, his grandfather also died early. 18-19 is a pretty tender age to lose a grandparent, and he was taking care of him for several years beforehand- likely more or less full time. Later years would be dominated by trying to take care of affairs alone and handle his only family's failing health, so I imagine his fondest memories are from before then. Early childhood things- being a tween or pre-teen set loose in the woods of his tiny island, coming home scraped up and dusty and tired to the man who would always have dinner waiting. A fond fog of his grandfather as the man who's rough old hands showed his smaller ones how to hold out feed for the amaro.

Loved, not fully understood, and by the end of his life, the last tether keeping him from escaping the confines of his island. He looks back on those times with a fond, bittersweet nostalgia for a man who had tried his best, gruff and unaware of who that little boy would grow to become.