The most terrifying thing in every universe... Copyright laws
I mean, the ondol system would be patents, and the crest theft would be trademark...but I guess even if inaccurate it IS related enough to copyright to just put it under the same banner
(The differences between the three are significant enough that I feel it important to make those distinctions, since copyright is mainly for "wholesale" products which can be manufactured again or replicated; while patents are specifically for processes and systems - the way of doing things; and trademark are symbology or representations that help identify a specific brand, service provider, or company from their competition.
And fucking up where you try to file what can get you into trouble later on for not managing to properly register your stuff, letting others steal the rights from you).