Ok then time for the reveal this has gone on long enough !
Ok the answer was Omega Halo now then let me explain step by step....
Riddle
The last of the big < Omega Halo was the last of the big Halo arrays
destroyed in the end It was destroyed along with the greater Ark
and began the birth of a new < This led to a second batch of smaller more powerful Halo arrays
At the sight of another great saviour < Omega Halo was destroyed near the greater Ark
and was the last stand of one such traitor < mendicant Bias fought here and lost the battle
the master vs the creator. < mendicant Bias against the forerunners
Clue 1
"One life hardly balances billions.” < Okay now at the start I though everyone knew about Omega Halo so I just put a hint that
Medicant Bias was there to make you think about Halos and get to Omega Halo but turns out no one knows about Omega Halo
Clue 2
I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely. (Revelation 21:6) < I thought this would point you in the right direction that Omega Halo was the last of the big Halo arrays and was the beginning for the new Halo arrays and the end for the big Halo arrays and that the fountain of life bit is about that the Halo arrays fired and so the waters of life flow freely now that flood are gone.
Clue 3
***** first made its appearance in Halo 4 < Omega Halo first appeared in the sixth terminal in Halo 4's campaign. The events depicted in this terminal were later adapted and expanded, (in a highly modified form), in Halo: Silentium
Clue 4
I am the start of a new and the end of another < Once again more direct than clue 2 and so I thought this would really make everyone get there this was also the point when I realised no one knew omega Halo
clue number 5
And so lives are lost In a instant but only by the small < I thought this would point to Halo arrays firing but only by the smaller ones
I hope that clears it up DONT KILL ME !
I appoint JL as riddle master..............