When Boruto: Naruto Next Generations announced it would be doing a special time travel arc in which Boruto met the younger Naruto, we had expected the arc to be a fun nostalgic throwback to the original series but things were immediately changed when Sasuke was thrown back in time as well. The two of them traveled back to the period just after Sasuke had abandoned the Hidden Leaf Village, and it was becoming increasingly clear that this would be good for Boruto and Sasuke's relationship as they look at this darker part of Sasuke's past.
After learning Sasuke's dark secret in a previous episode, the latest episode took things one step further as Boruto discovered why Sasuke left the village in the first place. And that includes the terrible fact that the Uchiha clan was massacred long ago.
Episode 133 of the series sees Boruto and the young Naruto bonding once more after their brief spat in training, and this gives them some down time. Asking Naruto about why Sasuke left the village, Naruto tells him the truth about everything. As Naruto explains, Sasuke left because he wanted to gain power. The Uchiha Clan was annihilated, and he's been wanting to get revenge as the sole survivor.
But Boruto's confused at this, so Naruto explains that Sasuke did it in order to sever all his bonds. Believing that the pain of isolation gives strength, Sasuke went along with Orochimaru despite Naruto's best efforts. Naruto refuses to give up, however, because Sasuke is the first real connection with someone that he's ever made.
This is all stuff fans already knew, but it will definitely change things for Boruto. Finding this stuff out about his teacher will certainly change Boruto's opinion of him much like seeing a new side of his father has changed his perspective. If things don't reset to the status quo after this time travel arc, then Boruto will be emerging from all of this a greatly changed character.
Originally created by Masashi Kishimoto for Shueisha's Weekly Shonen Jump in 1999, Naruto follows a young ninja, with a sealed demon within him, that wishes to become the leader of his home village. The series ran for 700 chapters overall, and was adapted into an anime series by Studio Pierrot and Aniplex that ran from 2002 to 2017. The series was popular enough to warrant a sequel, Boruto: Naruto Next Generations which is set several years after the events of the original Naruto story and features the children of many of its key characters such as Naruto and Hinata.