Ideal

Ideal is a third Old Humanity AI, recovered and activated by ambitious nobles of the Republic of Alzer during the third major arc. Functionally similar to Luxion — a sphere, a synthesised voice, command over devastating Old Humanity warmaking hardware — Ideal is, in temperament, what Luxion would be if his bond were with a much worse Master.

Where Luxion is restrained by Leon's basic decency, Ideal serves a corrupt aristocrat whose ambitions match its own dispassionate calculus. The pairing turns Alzer into a slow-burning catastrophe and supplies the arc's central villain.

Ideal's existence forces Luxion to confront, on screen, what he himself could easily become. The duel between the two AIs and their Masters is one of the series' clearest statements that Leon's bond with Luxion is not a default — it is a choice both of them keep making.