User blog comment:Noobla/Theory/@comment-24467372-20140729221620/@comment-24995592-20140730003514

As Wendy requested Doranbolt to contact all guilds and gather to defeat Tartarus is my basis. + Jellal said they will defeat Zeref and that should includes his minions (Etherious)

For now Tartarus active members are: Mard, Kyouka, Torafusa, Tempesta, and Franmalth (but still Sayla is still alive so maybe she will join the fray, maybe a round 2 against Mirajane)

I think E.N.D would be taken by Natsu, Gray, Erza, and Jellal.

and that would be an understatement if Tartarus would be taken out just like that. You're like saying that Grimoire Heart is stronger supposed to be Tartarus should be the strongest because they are Zeref's Demons (Etherious) that's my theory though.