He created the Lions through Altean alchemy, using an ore of unknown origin. It was imbued with a powerful energy known in our universe as quintessence. I would argue that the Lion's sentience makes them much more than just being ships, and Voltron itself is much more than a weapon, but--

[She frowns, looking down at her hands.]

I was very young when my father successfully made the Lions, and he was one of the greatest alchemists on my planet. And I am not my father; I cannot exactly understand how he built them while not fully understanding them himself.

All I know is that the Lions are not only sentient, but they evolve.