Magic and Hard SF

[Whitewings]

Originally Posted by Flyndaran

And some kind of limited energy or Fatigue that dwindles over time. That would give a pseudo-scientific feel while also keeping them from hanging around too long.
Oh wait, the Draining disadvantage, but no advantage to repair itself could work.

I think the Draining disadvantage is the best option; such a complex construction should be unstable, though it will be years or decades before anyone learns how to create such things. Ki manipulation theory (Thaumatology) is still very much in its infancy.