There are three different Spartan programs, I suggest making people who want Spartan characters look at this.
SPARTAN-I
It was created to test the effects of genetic enhancements given to volunteers that were part of the armed forces; this program is the least deadly and has the highest survival rate since there is nothing major or inhumane done to the body. These Spartans do not wear the same armor as other Spartans, so they could hardly be considered Spartans, more like Super Marines. While they are not quite as physically capable as the other Spartans, they still remain Human. The most notable Spartan-I is SGT. Johnson.
SPARTAN-II
The SPARTAN-II was the follow up to the original program. The SPARTAN-II program incorporated technology along with genetic enhancements to create even better soldiers. The most famous SPARTAN-II is the John-117, the Master Chief. The majority of the SPARTAN-II's die off during the program due to the extremely low survival rate, being no higher than twenty percent. Eventually this program was shut down due to it's inhumanity and insane economic costs.
SPARTAN-III
The SPARTAN-III program is the latest Spartan training program. SPARTAN-IIIs are not as powerful as SPARTAN-IIs in terms of strength, speed, etc. Rather, this program focuses on quantity, survival rate, and economic efficiency.