Well, what a coincidence--posting this on the day of Athrun's birthday. Happy birthday to you,
Anyway, this is another side-by-side comparison, this time of Athrun through the years leading up to the events of Gundam SEED Reflex
(an upcoming fanfiction). UPDATE, 6/6/2013:
Since Gundam SEED Reflex had been released, I'd thought I like to explain what happened to Athrun through the years leading to the events of SEED Reflex...
C.E. 68: Athrun, at 13 years of age, is called back from Copernicus City by his father, after attending a preparatory school. He gives his robotic pet bird, Birdy, to Kira just before he leaves. This would be the last time he meets his best friend, until a few years later...
C.E. 71: At 15 years of age, Athrun (enlisted in the ZAFT military in the wake of his mother's death) and his team are involved in the First Bloody Valentine War. He is first involved in the hijacking of five mobile suits at Heliopolis, and from there, he encounters Kira, who would happen to be fighting for the OMNI Enforcer military. Later into the war, both of them would eventually settle their differences and join together to end the war through an independent faction.
C.E. 73: Now at 18 years of age, Athrun sides and stays with the Orb Union at first. However, the events of the Second Bloody Valentine War had caused him to side with ZAFT again. Towards the later stages of the war, he would eventually defect back to the Three Ships Alliance and help Kira end the second war. He becomes an Admiral of Orb's military after the end of the war.
C.E. 83: Athrun continues to remain with the Orb Union, and continues to be in the Admiral ranking, 10 years onward. He also has the life as a father, as he was officially married to Cagalli Yula Athha eight years prior, and the couple having their only child since then.
C.E. 93: Two weeks before the start of the events in the fanfic, he is promoted to a three-star Admiral ranking. At 38 years of age, Athrun now controls most of the Orb military's operations, including the planning and coordination of mobile suit and infantry units.
---Gundam SEED © Sunrise