Here is how The Fellowship together again, Preparing for Battle in Berk and Reinforcements and more from Avalar goes in Yuna and the Three Kingdoms.
In Berk.
Crane: What are you seeing, Thomas?
Thomas: Are you all seeing what I think I'm seeing?
Nimbly: I think so, Prince Thomas! And it's getting close!
The four figures were Yuna, Snowdrop, Skyla and Twila.
Princess Luna: Yuna! Snowdrop!
Princess Yuna: Mama! Papa!
Snowdrop: Luna! Hiro!
Princess Luna: (hugs her daughters) We've missed you two so much!
Hiro: I thought we've never see you again!
Princess Yuna: Aunt Celestia! Uncle Duck! Sharon!
Princess Celestia: Yuna! Our beloved Niece!
Princess Sharon: We've missed you!
Prince Isamu: (kisses Yuna)
Prince Indy and Princess Anna: (embraces Yuna)
Duck: Those little ones missed you girls too.
Princess Skyla: Mommy! Daddy!
Princess Cadance: Skyla!
Shining Armor: Thank goodness you're safe!
Princess Twila: Mommy! Daddy! Nyx! Lilly!
Twilight Sparkle: Twila!
Flash Sentry: You're okay!
Nyx: We've missed you!
Princess Lilly Sparkle Rose: It's good to have you back!
Princess Yuna: Good to be back! The Fellowship is together again.
Iago: Guys! We've got a big problem!
Zazu: 5,000 Goblins, 5,000 Orcs and 5,000 Uruk-Hai are one their way to make their attack to Berk!
As the Vikings are preparing for battle.
Percy: I'll prepare for battle with the Maximals.
Rosie: I'll stay and keep the Mares and their Foals safe.
Princess Yuna: I'm ready for battle, Tigatron. I'm not afraid.
Tigatron: Patience, Yuna. There's still time for battle.
Airazor: And I'm starting to get so surprised how you've been friends with Smeagol.
Sméagol: And friends of Yuna is friends with Smeagol.
Princess Luna: I'll stay here with Isamu.
Princess Celestia: Same goes for me with Indy and Anna. Sharon. You help Hiccup lead.
Princess Sharon: Yes, Celestia.
Princess Cadance: Be careful, My daughter.
Twilight Sparkle: Stay close, Twila.
Princess Twila: Yes, Mommy.
Flash Sentry: We've got reinforcements!
Soon enough, The reinforcements arrived.
Shining Armor: James! Toby! Look! An army arriving!
James: Goliath and the Clans of Gargoyles!
Toby: And the Atlawa Tribe, Mabu Defense Force and Hunter an the archers of Avalar!
Hiccup: Open the Gates!
The vikings opened the gates and the Atlawa Tribe, the Mabu Defense Force and the Army of Avalar entered the fort.
Princess Luna: Hunter! How is it possible?
Hunter: I don't know.
Kane: But Hunter met them along with Smeagol and invited them to a battle against Chernabog's forces of evil.
King Solar Flare: You and Kane are most welcome, Hunter.