Gojo/Geto, No Preference: Best Friends, Foes, and Wives

Gojo is Gojo Satoru, and Geto is Geto Suguru. I vaguely remember that their surnames are opposites, meaning something like impermanence and heterodoxy (I think).

They're such a good match, both in sound and in meaning.

Almost all their traits are symmetrical, contrasting, or corresponding. The author said they designed them as complete opposites while drawing them.

In Volume Zero, Gojo stands on one end of the plank, right at the edge of the cliff, while Geto, the cult leader, stands suspended beneath the other end.

Theme: The gentler someone is, the more they have to bear in their heart