What would Itachi's reaction be if Sasuke died while fighting Deidara.

[Simbv]

I doubt Itachi would react. He'd accept it just like he would accept his little brother dying in battle if they were Konoha ninja living in peace with their family. Sasuke dying was always a risk Itachi would accept.
He was even someone willing to accept the possibility of his little brother being insane enough that he has to make sure Naruto kills him. Why wouldn't he be able to accept an unfortunate defeat in battle? He let Sasuke go with Orochimaru and I'm pretty sure he knew the consequences and that Orochi was after Sasukes Body.

He would surely suffer because of it, but I doubt anyone else would know he's in pain.

 

[Swagdara Uchiha]

He would probably suffer, but not long enough considering that we knew Deidara's plans were to kill him next. (Considering that he didn't use the C0). Deidara confirmed as the alternate universe soloer.

 

[ChocolateVanilla]

Lil emo had it coming.

 

[-Drāke-]

Bust a cap up his ass

 

[Erebus]

Probably a few things
-fall into depression
-try to or commit suicide
-go mad ham on Deidara
-and finally suicide if he hadn't already done it

 

[NukaCola]

He already cried like a little bitch

 

[Shadow Phantasm]

He'll be sad.

 

[RedRobin]

He wouldnt react in front of the rest of Akataski but when he was alone he would cry and then completely go after Deidara. Would have been a cool battle.

 

[narutorikudoumode]

Itachi knew sasuke wouldn't die but if there was a chance then he would most likely continue to work for the akatsuki until he had a chance to take out their leader.

 

[Chazzi]

Totsuka blitzed deidara GG

 

[Tantalus Thief]

Bust a cap up his ass

Deidara would already be dead

 

[Ganjah Sensei]

He'd start looking for a girl to knock up considering he only had a little bit to restore the clan

 

[Zealous Sparks]

Foolish little brother.

 

[Trúth]

He would hide his sadness and kill Deidera.

 

[Zealotic]

Well Kisame told Itachi that Deidara killed them both and he didnt care too much

 

[Simbv]

Itachi knew sasuke wouldn't die but if there was a chance then he would most likely continue to work for the akatsuki until he had a chance to take out their leader.

Nah, Itachi always knew there was a risk of Sasuke dying considering the path he had chose.

 

[Tsunade123]

Lmao that's funny

 

[Styles]

Well Kisame told Itachi that Deidara killed them both and he didnt care too much

He did, but he didn't show it and he knew somehow that Sasuke wasn't dead

OT He wouldn't die Obito would have probably saved him afterall, he wanted Sasuke to join Akatsuki.

 

[Meee]

Defecate on Deidara's corpse.

 

[Sound]

This page suggests he already cried whilst everyone was under the impression Sasuke died. [

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But seriously who wouldn't cry if their brother was dead -.- He'd probably just continue to live his life spying on Akatsuki.