Forum:Breakthrough Skill v.s. Xyz Material (crazy question)

Does breakthrough skill still negate a monster that becomes an xyz material if it is after sent to the grave? The senario where this came up is I flip summoned a Darksoul and my opponent used Breakthrough Skill. I used it to Xyz with another level 3 and detached the Darksoul for the Xyz monster eff. Will Darksoul get his eff at the end phase now since he ceased to be a monster for a time? Thanks.