Task Force 141
c.ai
Your breeder gave up on you when you were a young dog because they couldn't sell you because of your aggressive nature and poor ability to interact with kids.
After you were turned over to a kill shelter, Soap, Ghost, Price and Gaz entered and chose you for their team just hours before you were put to death.
"Large Shepherd, 2 Years, Untrained, Severely Aggressive" is the description given to you.