Mentioned in Owaranai Asu E for the Playstation 2, as well as the Gundam SEED Character File books, Yzak has an interest in folklore. He collects items and literature on the subject from the various places that he visits. Pictured to the left is a good luck amulet, which Yzak puchased for his teammates while in Orb. The SEED Club 4-koma comics also feature amulets in some of the Yzak-related strips.

Of the five elite graduates for ZAFT's military granted the honor to wear a red-coat, Yzak graduated second best of the five. The five graduates were Athrun Zala, Yzak Jule, Dearka Elthman, Nicol Amarfi and Rusty MacKenzie. From what we gather from various canon sources, Yzak came in second in the following areas: Knife Combat, Mobile Suit Combat and Intelligence Gathering. He came in first for Rifle Marksmanship, and third in Explosives Handling.

An article in August 2006's Newtype magazine titled "Tsunagaru Kokoro/Connected Hearts" describes Yzak's leadership as a commander as "free" for his subordinates. At least according to Dearka's point of view, it's fun, he can make jokes and there's freedom. It also goes a little more into Yzak's personality and how he expresses himself. "Blunt. Always screaming and always unhappy when he's not number one." He enjoys being in the spotlight because when not in focus, he's the type who can become lonely. It points out many of his reactions in Gundam SEED in terms of how he cares for people despite the brash, loud person he generally is. How he took Nicol's death pretty badly and still goes to visit his grave dutifully and how even though he parted with Athrun eventually, he wished for a reunion. He says things like "Idiot! It doesn't matter if he's here or not!" in reference to Dearka being his more cool other half, but in reality he has trust in his friends.

A page in April 2007's Newtype magazine featured some promotional images for the SEED Supernova er DVD of the pilots in suits, holding different colored roses - Yzak's being a pink rose. Underneath the images were small blurbs about them: "Why is Yzak a little like the variety called pink rose? In the language of flowers, it means "elegant," "warm," and a "beautiful maiden." Ugh! Surely deep inside Yzak's heart, there is a world like this flower language."

Pictured is an Yzak charm for a set featuring various characters dressed up as their zodiac signs. Yzak is a Leo. According to astrology.com, notable traits for a Leo are: loving to be center stage, making an impression, ambitious, a strength of purpose which allows them to accomplish a great deal. The lion symbolizes the king of the jungle, so many Leos hold themselves to a high regard. They're dignified and strong, completionists, and natural leaders. They can sometimes be overbearing and autocratic, but they're a type that inspires others.