Naruto: The Seal of Legacy

Before their death, Naruto's parents not only sealed the Kyuubi in him, but also left him one gift, thanks to which they will be sure that he will become the greatest ninja of all time. But what is this gift, and how will it help them see their son in the future? * * * * * * * * * * Note : There will be a harem, lemons, and of course a faster development of the MC.