all i could think of is this manga ---> http://www.mangago.zone/read-manga/ouji_no_hakoniwa/
FOR MORE INFO: I believe it's part of one of those combo ones? Like one of 2-5 stories in a book? It's casual for a bit, but at the very end the "masters" sheet falls off and one of the last panels is of his foot that has a chain on it. The butler seems to be keeping him? Like somewhat possessive or yandere-ish? But you don't see it until the last second? And I think it had the wording "but all is not as it seems." In the description for it? I'm not completely sure.
For everyone! I came across it randomly!
It's called Beautiful Cage, and it's ch.5 of > http://www.mangago.zone/read-manga/shousetsuka_no_shitsukekata/
Careful though! Ch.4 has shotacon in it. ヾ(❀╹◡╹)ノ~
There's this one book that has a one-shot where there are maids, a butler, and the master. The maids are new and they talk about the master-butler relationship. It seems like the master is completely bossy and rude, and orders his butler around a lot but at the end, a sheet falls off and we find out that he's actually chained up and not really the one in control. I read it once before but now I can't find it. ( ̄∇ ̄") ╮( ̄▽ ̄)╭