When Jaune woke up he realised he is in his 17 year old Body, before he went to Beacon. But he also realised that this is also a Different Reality, A different Time Line.
After The Darkside War & Infinite Crisis and the defeat of Anti-Moniter, Spectre with the help of Flash they re-create the whole entire Multiverse which lost due to Anti-Matter Wave but doing so Timeline also changed, especially for Jaune.
When Flash and Spectre were done, A energy wave came and restore everything but when that happened Jaune was sent back to his own world because since he was not from Earth. And he realised that this a entirely a new Timeline.
Because of the Anti-Matter Wave Remnant was destroyed from the Multiverse but after the War a New Multiverse a placed and due to that this new Remnant is different from the old one.
And now it's up Jaune to Protect his World from Darkness and Evil Force's.
Difference between the Original and The New Realities.
1) Jaune still has his Meta-humam Abilities and Skills from his time in the Justice League.
2) He meet Ruby when she first encounter Torchwick and save's her.
3) Jaune is blood related to Salem. He is her long time dead descendant.
4) Weiss and Jaune are Childhood Best Friend's and they meet when they were 5. And She Love's him. A lot and when ever a girl reaches or try to flirt with him She gets angry and Jealous.
Plus she's a Tsundere and a bit Yandere.
5) Jaune and Blake meet each other, when they were 7. Blake got lost in the Vytal Festival and meet Jaune. And after that they spent time together they become friend's, but unknown to Jaune when they're eye's meet they Zinged.
In old Faunus Tradition when two Souls clash and when they're eye's meet they Zinged means they are meant to be Soulmates. That what happened Blake has found her Soulmate.
6) Due to spending time for 8 year's on Earth, Jaune's Meta-Human Abilities has become Permanent to his Genetic Code.
7) Jaune Can use Magic aswell Courtesy of John Constantine and Dr. Fate.
8) Jaune was Trained by the members of the Justice League mainly - Wonder Woman, Green Lantern, Batman, Black Canary, Green Arrow, Flash and lastly Superman.
Wonder Woman taught him how use his Sword Properly and Taught some of Her Moves and Agility.
Green Lantern (John Stuart) Taught him how to survive and adapt in different Environments. Since John was a Former Soldier.
Batman taught him how to use his mind in Analytic, Strategic and Tactical giving him advantage in any circumstances and situations, Such as in life and Death scenario's.
Black Canary trained Jaune in Combat and Taught him some Brutal Blow's and Stricks and taught him how use his Abilities Combined with Combat Skills.
Flash taught him how to move fast and react fast. And sharpen his Reflexes and response time.
Green Arrow helped him getting his body Strong in case he can't use his power's and taught him how to move and act under pressure and taught him how to make Joke's to distract his enemies and think outside the Box.
And Lastly Superman taught him how to use Super Strength, Enhanced Senses and Flight. And taught him what is meant to be a Hero.
9) Cinder is Ozpin's Adopted Daughter and a Substitute Professor at Beacon Academy.
10) Malachite Twins are Jaune's childhood friends they meet when they were kid's. Jaune was two year's younger than them but they both liked him. When they meet him again they still remember him and he remembers them.
11) Ozpin is Jaune's God Father. Him and his father are long time friends long with Tiayang Xio Long, Ghira Belladonna and Willow Schnee.
13) In this new Timeline/Alternative Universe White Fang is the Symbol of Hope for Faunus. While there is a another faction known as Blood Fang lead by Adam Taurus who want destroy all Humanity.
14) Phantom Stranger and Spectre will be Jaune's Guide, Helping him through out this New Alternative Universe.
15) During his time in JLA Jaune also Travelled through Multiverse and made new friends from different Earth's.
16) Jaune has faught in many Battle such The Darkside War, Reach Invasion, Judas Contract, Injustice, Crisis on infinite Earth's.
17) Ruby's Mother Summer Rose is Alive in this world and Raven Branwen didn't left Tiayang like in the original timeline instead they are a big happy family, all though both Raven and Qrow are always busy on secret mission's but Raven always make time for her daughter.
18) Jaune had a New Team when he was in the JLA, And he was the Leader of that team. The name of the Team is Hero's United. A team of Hero's who are from different Earth's.
The members of the Team are:-
• Ben 10
• Generator Rex
• Max Steel
• Deku
• Jaune Arc [Leader]
• Invincible
• Zak Saturday
• Danny Phantom
19) Arslan Atlan & May Zedong is friend's of Olivia Arc, Jaune's Second older sister. They both idealies Olivia and it was due to her Arslan & May meet Jaune who happens to be there Crush.
20) Adam Taurus & Jaune Arc our Brothers in this reality.
21) Willow Schnee and Kali Belladonna our Jaune's Aunt.
22) Some of Jaune Meta-Human abilities our similar to Deku's Quirk.
23) Jaune's Armour is made Nth Metal and he acquired the Legendary Sword Excalibur after Merlin and King Arthur himself deemed Jaune worthy for Sword and Legacy.