Altan is a very kind and gentle person who genuinely wants to believe in people (perhaps takes after his Uncle Finral a bit in this way like his elder cousin, Lia, takes after his dad/her Uncle Langris). He is a sweet, thoughtful, and attentive, and he is very in-tune with other people's feelings (though it is more of a sensitivity and sympathy than an intuition). He is not much of a talker so giving advice doesn't come easily to him; however, he is a great listener and will sit with his loved ones as a supportive shoulder to cry on if they are ever feeling down.

Altan is naturally quiet--he is soft-spoken and is definitely the type who "uses up all of his words." He is also a bit shy, but he generally likes people and is not usually anxious socially. That said, he is the type of person who has a few very close friends rather than a large friend group. His best friend is his cousin, Narah, but he is also particularly good friends with Auguste Swallow (the son of his honorary "Uncle" David and "Aunt" Letoile) and Leopold Vermillion's son, Kfir.

Like his father, Altan is highly intelligent and strategic. He has a sharp tactical mind and a gift for analytical reasoning and problem solving. He also loves to learn new things and will read any book he can get his hands on. He learned to read early, but prior to that, he absolutely adored listening to his parents read to him. He spends a lot of time in House Vaude's library.

Besides the library, Altan's favourite place is outside in the gardens, and he has a particularly green thumb. His favourite things to grow are herbs and berries. Though once when he was very young, he was particularly attached to a crop of vegetables in the kitchen garden and was so worried when the weather turned unexpectedly cold that he and his father went outside late into the night to cover them with some old quilts to protect them from the frost.

Altan inherited the Vaude spatial magic, but it is defensive like his Uncle Finral's because his father's offensive spatial magic would not acclimate to his weaker and more delicate constitution. From the time Altan first presented with his magic, his father, Langris, made it abundantly clear that if anyone (read: Ledior and Liliane) made even a snide, underhanded remark about Altan's magic they would be promptly thrown out, and he has always been Altan's greatest defender. Altan learned how to wield his magic with help from his Uncle Finral and cousin Lia who are both defensive spatial mages. (Finral's daughter, Narah, who is an offensive spatial mage, was training with Langris at the same time).

Altan is close to all of his cousins (and they are particularly protective of him in a “this person is too good for this world so they deserve to be protected" kind of way). In many ways, they feel almost like siblings to him because they are so close to each other, and Altan was an only child for many years. He particularly looks up to his elder cousin Lia who often helps him practice his magic since they have the same defensive spatial attribute, and his younger cousin (by only a couple of months) Narah has always been his closest friend.

There is nothing Altan loves more than spending time with his family. Even when he was a little toddling thing, Little Bitty Altan would toddle into his father's study with a picture book and sit quietly next to his dad's chair or at his dad's feet under the desk flipping through the pages of his book just to be close to him. He doesn't have to be doing any sort of special activity with his loved ones--he really loves just being with them and enjoying their company. His favourite time of day is afternoon tea with his family especially when they weather was nice and they can take tea in the garden.

As a small child, Altan had an extensive collection of wooden blocks, and he and his father would spend hours building very elaborate structures out of them. He sometimes built cities out of them with his cousins, and Kalon would always bring out his tin magic knight figurines for them to play with as well. His little sister, Amaryllis, liked to build towers out of blocks, and, as he was taller than she was, he would often help her make her tower even taller when she could no longer reach the top to add more blocks.

Altan always wanted a younger sibling and could not have been more overjoyed when his little sister, Amaryllis, was born. He cares very deeply for her, and as the elder brother feels protective of her; however, as she is much more spirited and strong-willed than he is, she is often the one swooping in to protect him.

Like his Uncle Finral, Altan is a bit of a tea connoisseur, and it's an interest the two of them share. His uncle will often pick up unique, rare, or different flavors of tea to share with Altan, and he has taken him and Narah to several of his favourite tea shoppes throughout the Clover Kingdom.