Board Thread:Versus Debates/@comment-44829986-20200426232150/@comment-32685487-20200511171233

Flying Raijin is not unique to Minato, Tobirama invented it and the Hokage Guard knows how to use it to warp to and from Tsunade. Not to mention it says Hiruzen knows every jutsu in Konoha, so the ones he can't use he knows how they work and what their weaknesses are. FTG isn't a Hiden or a KKG so in reality if Hiruzen really cared enough to, he could learn to use it. There is really not a reason why he doesn't use it in the series besides the fact they wanted Minato and Tobirama to shine with it