The primary vehicle for each power-tier reset (Super Saiyan through SSJ3) — his arc defines the show's escalation pattern.
Mirrors Goku's tier progression from rival to ally, with a character arc built around never quite catching up.
First major villain scaled specifically to force the introduction of the Super Saiyan tier — a genre-defining antagonist.
Progressively sidelined once the Saiyan power-tier system takes over — widely cited as the show's clearest structural weakness.
The writers stopped tracking concrete power-level numbers after the Frieza saga specifically to allow continued escalation without being constrained by earlier stated figures.
They lack access to the Saiyan transformation tiers (Super Saiyan and beyond) that define later power scaling, which sidelines them structurally rather than through any individual story choice.