The Group Sibuna Was Created In Season 1 Of House Of Anubis When The Gang Discovered Evil In The Anubis House From Ghost,Egyptians And Many More Evil The Name Sibuna Comes From The Word Anubis Which Is The School Name Backwards They All Stick Together To Find Out The Mysterys And To Fight Evil But Through The Seasons.More People Of The Sibuna Group Were Leaving And More People Were Joining The First Person From The Group That Left Was Nina Martin Which Was The Only American In The School Because All Of Them Were British And She Left After Season 2 Of House Of Anubis But Was Replaced In Season 3 By K.T Which Was A New American In The Show But Not The Only Because Eddie Came In Season 2 And He Is Also American Also In The Group That Left Was Amber Which Left To Go To A School Somewhere Else.In Season 1 The Mystery That They Had To Solve Is The Mysterious Disappearance Of Joy  Patrica's Best Friend Since She Weirdly Left In The Middle Of Class In The First Episode Of House Of Anubis Ever Since Nina Showed Up People Suspected That Was Was Involved And Is Her Replacement But She Is Not Involved At All.