A Useless Mecha? Bind the Ancestor of Cultivating Immortals at the Beginning

I dressed up as a useless mecha master on the interstellar battlefield. The mecha was rated F, and the whole team laughed at me. However, they don't know that the core of my mecha is actually an ancestor who failed to overcome the tribulation. Every time it kills, the mecha devours the enemy's energy, and the ancestor's remnant soul recovers one point. When the enemy ship dispatched the SSS-class mechanical behemoth, I pressed the unblock button. The runes on the surface of the mecha lit up, and the ancestor's voice resounded across the starry sky: "Junior, watch carefully, this sword is called Kaitian——"