Kalin enters Neo domino city to visit old friends. one of the friends he visit was Yusei. They had a brief talk then Kalin decides to go to the old ener-D reactor. At the reactor he learns of bad news. Kalin then shares the info with Yusei.

Kalin had also discovered his strange power since revival after his defeat as a dark signer wondering what it was he goes to team 5ds for answers. He discovers it was linked to the ulitimate god , the crimson dragon. Wanting more answers he and a member of team 5ds go to the nazca lines. Kalin then enters a zodiac duel to face the darkness in his heart and was sucessful. He obtains the card void ogre dragon from the ritual.

Kalin and Yusei later a fight because he let the power he got from the use of the duel dragon card 'void ogre dragon' being called a signer dragon. This is due to a manga ref of it being a creation of the ultimate god the crimson dragon.

Yusei had no choice but to use force and use axcel synchro to quell kalin. Since the crimson was originally summoned by goodwin it would had left the signers at the end of season 2. because the crisis with the earthbounds. Yusei entered the pact and called the crimson dragon useing his signer dragon stardust dragon. the result of this pact causes his and the rest of team 5ds to regain their marks of the dragon but this time the mark of the dragon will act like team ragaroc ruin eye.

During that battle it was no longer a normal duel as his full power was used it was the final judgement. just like the battle between 5ds and team ragnaroc to see who can challenge team new world.
Kalin lost this battle causeing the signer dragon he has to lose power , kalin becomes a shadow drone and starts a shadow army

kalin basically let the power get to his head

as the situation got worse . and time running out team 5ds has no choice but to call the nordic gods for aid. they contact the leader of the team Halldor. halldor accepts the request and lends their aid to help team 5ds. Team 5ds choose to spare kalin and ask halldor to carry out judgement again.
his team is able to expel the darkness by attacking the summoned signer dragon kalin has in his deck at full power by useing polar star god loki. dealing real damage to kalin but does not kill him and re connect him with the crimson dragon.
by the end of the duel. kalin decided to step down decideing he did not deserve to be a signer and give the card to halldor.

Halldor then returns the signer dragon to Yusei telling him that Kalin wishes to leave to his dismay. Yusei was saden by the news but decides it may be time to move on. With the aid of team ragnaroc team 5ds enters the spirit world.

Yusei feels anxious as the final battle draws near he wants to save him but can he do it alone. " Can I really fight my own father "
His brothers console him " you know it must be done . But you are not alone you will have us "
" Yeah all of us "

Yusei defeats Dr Fudo in the final power useing the combined power of the gods as a result. it revives Dr fudo but he passes out soon after and was taken to a hospital.

Yusei stays by his side as tears fall from his eyes
Holding his father's hand he hears a voice " you did it.. it's all over you do not have to fight anymore we are together now as a family "

Possible On the good end there will be a season 2
kalin returns with void ogre dragon. And there will be another 3 new signers likely to be original characters. More Manga reference ( Duel Dragon , Meklord , Nordic cards , Timelord )

Now with the crimson dragon's power at it's prime the stars of destiny have all been gathered . They all now guide the world to a better future...