Piccolo understands that his current power is insufficient. He decides to reunite with Kami, effectively ending the existence of the Nameless Namekian’s two halves.
Dragon Ball Z Episode 137, titled is a pivotal moment in the Android Saga. It focuses on the desperate realization that the Z-Fighters are completely outclassed by the new Androids, leading to a massive shift in Piccolo’s character arc. Episode Summary Dragon Ball Z Episode 137
This episode marks the end of Piccolo being "just a rival." He chooses to sacrifice his individuality for the sake of the planet. Piccolo understands that his current power is insufficient