If i played Call to the Grave and i have a zombie out and all other players have nothing at the end of there g?

every time I play Call to the Grave people say i have to sacrifice it at the end of there turn since they have no creatures, now is this true or can i leave there just to chill?
Update: the thing is that the people i play against say that battlefield is there's and nothing else so are they wrong or am i wrong about my battlefield counting too?
2 answers 2