Seiya Ryuguin is overpowered but overly cautious. After being summoned by the breasty goddess Ristarte in an attempt to level up her godhood, Seiya spends his entire isekai'd life grinding out pushups and beating up other gods to max out his stats. The Demon Lord in another world can wait as Seiya gets swol. He's the Cautious Hero.
After the death of her older sister, Peta, Null decides to just replace her with a robot. Null & Peta is a metaphor for the dystopian ultimate future of capitalism: A world where all corporations control all capital and have replaced labor with automation which creates a majority underclass of unemployed and destitute people. Hmm, maybe pure capitalism is bad?