Grell is in Undertakers shop and they are discussing a mission that Grell has to participate in and he had to take someone with him and he chose the most experienced Shinigami he could find in Britain which was Undertaker oblivious to Grell's plan undertaker accepted Grell's plan was getting underway.

A few days of travelling they chose to stop at a fancy in which Grell had organized and specialized that it had sound-proof walls. Grell had suddenly sprang on undertaker and put a headlock on the Shinigami temporally making him lose his balance which he got back in a few seconds and he tried to knock Grell off but he grabbed his hand over his mouth and slipped a bottle that dissolved in Sylvia and then Grell hit a swallow reflex that made Undertaker swallow the liquid the undertaker started to get a bit woozy and fell down Grell had gotten off of him by that time and was standing over him staring at what he had done all of a sudden undertaker stood up and said " I want to obey you now master " then he bowed and Grell had his wish half fulfilled now he knows it worked on Undertaker now he had a 95% chance that it would work on Sebastian-Kun.