What is Natsu strongest Form?

[RebirthArtOFC]

So... I have a doubt here, what of those one is Natsu strongest form? Fire God Dragon Force or Seven Flames Dragon Mode? I mean, Seven Flames Dragon Mode defeated Acnologia with a single blow, but Fire God Dragon Mode posses the power of Ignia, whoise stated being able to surpass Acnologia, but i really have this doubt... And i know how powerful and overpowered Savage Fire Dragon Mode is, but it was unable to defeat Acnologia so... (NOTE: I am not counting the base power of Natsu when he used both forms, i am talking literally about the transformations)

 

[DemonGodMitchAubin]

Seven Flames Dragon Mode is his Strongest Form based on the knowledge we have

 

[Vampire_Vamp]

It's a shame god serena was killed, Natsu could of used eleven flame dragon mode XD.

 

[RebirthArtOFC]

It's a shame god serena was killed, Natsu could of used eleven flame dragon mode XD.

Well, God Serena actually had 8 Different Dragon Slayer Magics, but only displayed 5, so natsu could use an fifteen flame dragon mode! (But we should remember that God Serena displayed Lightning, Fire (Or "Purgatory") and Wind (Or "Gale") Magics, which are Elements that Natsu already have on his arsenal, we don't know if the other 3 are simply renames of already existing Dragon Slayer Magics or indeed totally new Magics)

 

[Vampire_Vamp]

He would enhance his flames with more flame elements

 

[Vampire_Vamp]

He would enhance his flames with more flame elements

Gale and air for hurricane dragon slayer