I'm sorry but going on how you "have no control" what Undertaker does (especially when it was something you didn't want him to do) does not come off as good RP editique, as nothing should be blurring the lines between IC and OOC like that.

And while it is sometimes possible that characters might not respond to something as planned, what I don't understand is the thing holding Undertaker up is the way how shinki function. Which shouldn't be brand new information to you as everything is already clearly stated around the comm. I don't get how that information could have been missed, or why bother making him a shinki at all if you're not going to fully look into it.

It's the things like this that honestly makes you seem unreliable and wary to play with.