Finally, "NCIS: Los Angeles" fans got the answers they've been seeking. Callen isn't just a mystery baby left behind when he was young. His memories weren't magically erased, leaving with no first name outside of G. We finally know something about Callen's past, including his tie to Hetty. It wasn't exactly the past we might have expected, but it explains so much about the way Hetty treats him and his own anger issues.
What We Know
Chris O'Donnell's character NCIS Special Agent Callen learned more from Hetty in just a few minutes that he knew his entire life. He discovered that his mother was Romanian and Hetty was her CIA handler. In her desperation to keep her children safe, his mother escaped to America. After several years, she returned home. During this time, the Comescu family was attempting to continue their vendetta against Callen's family due to a betrayal during war times.
The end result was Callen watched his own mother shot to death on a beach in Romania. Hetty blames herself since the CIA called off the meet between Callen's mother and Hetty at the last minute, leaving the mother vulnerable to attack on the public beach. Hetty then took it upon herself to watch over Callen from a distance, eventually bringing him on at NCIS.
This explains why Callen only had glimpses of memory. Having experienced a serious trauma at such as young age, the mind automatically tries to save itself by suppressing the images. Having seen his mother shot, he developed and continued to carry an internal anger. Without the memory at the forefront, his only explanation for the short temper and cold attitude was simply not knowing who he was. The combination of not knowing and horrible memories equals the Callen we've gotten to know.
What We Don't Know
The one thing Hetty couldn't find out about Callen was any information on his father. She knew, though Callen had already discovered, he had a sister. But why wasn't the father around for his two children? Hetty has no idea what his name is or whether he is dead or alive. The possibility remains that he is alive. However, during Hetty's time with the Comescu, the leader stated the vendetta would end with Callen. Since Callen's father wasn't actually a relation of the rival family, he may still be alive. This is still a story line "NCIS: Los Angeles" is looking to explore.
A Better Callen
Having a past has helped Callen reach a sort of peace or balance he never had before. Being able to see pictures of his mother and know he was loved has softened him. This will help him become an even better agent than before. Now, if he could only find his father, he would be able to discover the whole story.