ACE 4 by Adam Moon
The final installment of the Space Cadets series:
Jack Peterson just died. Luckily his consciousness was saved just in time and teleported into an A.C.E. suit.
When he wakes up aboard the Conquistador warship he finds out that the Bleeder planet is close by. When reinforcements arrive, the attack will finally commence.
When a Bleeder ship far larger than any warship they possess appears and fires upon them, they must defend themselves.
But the Bleeder ship and the Bleeder planet hide an unexpected and welcome surprise.
There is a warship called the Dreadnought that is full of two thousand mech soldiers. All of the soldiers' bodies died a long time ago and over the years, the mechs have gone insane. When the Dreadnought arrives in orbit around Bleeder, all hell breaks loose.