Taegan Smith was described as looking almost exactly like Caine Soren, his son. This means he had dark brown hair and black eyes, and was otherwise very good-looking. He was also described by Connie as an intelligent, careful, kind man.
- Before the FAYZ
Taegan Smith is implied to have had a criminal past, causing him to take on "Smith" as a surname. At some point he met and married a young Connie Temple, who started cheating on him. They had twin boys who Connie named Samuel and David after Biblical figures, and David looked almost exactly like Taegan.
Taegan Smith was killed fifteen years before the FAYZ, when a meteorite hit the nuclear power plant where Taegan worked and dragged Taegan's body deep underground. The impact of the meteorite also led to radiation from the power plant flowing down the hole it had made. An alien virus that was on the meteorite mixed with Taegan's DNA. The radiation caused the virus and human DNA to mutate and grow into a single creature.
This is the reason for Caine and Sam having four bars, as because of the genetic connection, the Gaiaphage had a stronger hold on them. They should be the most powerful, but Little Pete is easier to tamper with, due to his autism.
Teagan Smith was not originally believed to be Sam's father. However, it is revealed in Light that Connie took blood samples of Caine and Sam after Caine started attending Coates Academy, and discovered that Taegan is in fact the father of both boys.
The Gaiaphage, which is made up of Taegan's DNA, possesses Gaia Soren-Ladris. This means that although Caine is Gaia's father, Gaia is technically his father as well.