Why didnt Nagato just bring Yahiko back to life?

[ANBU Kakashi23]

suicide bro lol, sure it was nagato's knife, but by no fault/jutsu of his own did yahiko die.

dont get technical , nagato had the knife, he sure as hell didnt have to grip it so tight , could of stabbed in a non vital area, w/e xd

 

[Jukain]

bring back Yahiko?....silly goose the reason why is because Yahiko is from a different anime....Rurouni Kenshin ring any bells?

lmao, funny they both use swords.

 

[arv993]

he should be able to as he planned to do that for madara. but i bet tobi made sure it was only used for him not for nagato himself