Decas main purpose??

I know some stuff about juice but I am wondering exactly what Deca is used for in a cycle. I have heard of it used in cutting cycles, bulking cycles, and hell some people just use it so their joints don't get sore. I am currently taking 150mg of QV deca EOD and am on day12. I am stacking it with dbol and test prop, which I know was a bad first timer choice, but what the hell it was free. I have gained 10lb.s already but the Deca won't even kick in until week four. Just wondering how the Deca will affect my cycle thanks for your input.

if you've done more then one cycle with and without deca you will notice a difference in the joints when liftin heavy, i also get some strength with it but not lots, its a good additive for any cycle, i perfer EQ

i believe that deca increases the protien synthesis in muscles and creates a positive nitrogen balance. basically, with enough protien/calories, deca helps muscles GROW.