結構前から設定練ってた子
鎧兵士はアーティファクトで、契約すると契約者からエネルギーをもらって自立稼働する
契約者は代償に過度なエネルギーを消耗するので空腹感に苛まれる的ななんとか…(˘ω˘)zzZ

I've been polishing this girl's design since a while ago.
The armor knight is an artifact that moves on its own by receiving energy from its contract partner.
Energy drain from the contractor is significant, so they are constantly hungry, or something like that...(˘ω˘)zzZ