Here is a serie of Idea I had based on many readings (manga, novel, fanfics) watchings (TV series, anime, movies)

NarutoXGankutsuou

BIG PICTURE

Naruto is betrayed

meat with a supernatural being (may or may not be Kyuubi)

try fusing with it (the seal could interfere and rip the being from it's powers an giving them to naruto

the scene of the fusing would be as folow:

Naruto is weeping

Gankutsuou -Mon ami...

naruto does not react

Gankutsuou -Mon ami...

naruto react

Gankutsuou -Mon ami...

naruto see an (object/body) with reflecs on it

Gankutsuou -L'espoir...

(refect show for exemple the beging of the sasuke retreving mission)

Gankutsuou -Le chagrin...

(sakura crying)

Gankutsuou -Le désir ardent...

(Naruto determination to bring Sasuke back)

Gankutsuou -La résignation...

(Chouji, Neji, Shikamaru and Temari, Kiba and Kankuro, Lee and Gaara)

Gankutsuou -La colère...

(battle against Sasuke)

Gankutsuou -La terreur...

(RASENGAN VS CHIDORI)

Gankutsuou -Le desespoir...

(sasuke going to Oto)

Gankutsuou -Et à nouveau l'espoir...

relect show naruto has he is

Gankutsuou -Cela fait des milliers d'années que j'attendais, à l'interieur de cet (objet/corps), la venu de quelqu'un comme toi.

Naruto -I... I...

Gankutsuou -Je suis avec toi...

Naruto -I...

Gankutsuou -Et tu es avec moi...

Naruto -...

Gankutsuou -Je te donne ma sagesse et mon pouvoir...

Naruto -...

Gankutsuou -Et toi tu m'offre ton espris et ton corps.

Naruto -je...

Gankutsuou -Le pacte est conclu...

Naruto -Je suis...

Gankutsuou and Naruto -Gankutsuou(underworld king)