Thread:Gokyr586/@comment-39007672-20191223103211/@comment-26018994-20191223140736

For that, I guess the proper explaination is that even though some Legend Devices, like the Heisei Rider Lockseed you mentioned, is used by an evil Rider (in this case, Fifteen), it's still a Legend Device since it harnesses the powers of the actual Heisei Riders themselves.

Anyways, this topic is still debatable, but it is a good question nonetheless.