Temprina
After beating the champion Marv waits outside your house and asks you to come with him to meet Gunter in his house in Altara Town.
There he will give you the Order Bell which you can use to summon Temprina at Peak Point.
Yveltal, Xerneas & Weather Orb
After encountering Temprina at Peak Point (Post Game) go back to Gunters house and Marv will ask you to summon the Savior-Pokémon.
Starting with Yveltal you will meet up at the Altara Temple to place the first artefact.
Then you meet up again at the Hanera Temple to place the second artifact which actually let's Yveltal appear.
After encountering Yveltal Marv asks you to go to Lake Brevis.
There you will place the third artifact on the shrine on your own.
Then head to the Aster Woods where Marv already awaits your arrival.
After putting the last artifact on the shrine Xerneas will appear and can be caught.
Marv will then ask you to meet him at the peak of the Igno Vulcano for a last battle.
After defeating Marv you'll receive the Weather Orb which we will come to later.
Zygarde & Vitado Ticket
Before your encounter with Temprina you'll find an item inside the Order Bell.
After the encounter head to Prof. Tribus in Flopetal Town where he will tell you something about his researches he's been doing throughout the game.
He asks you to collect the 10 Zygarde Cells and then bring them to Unitum Grotto on Isle of Unity.
Barmoss Town Trainerschool Backyard, Rockiff Steep Cliffs on the far east, Lostor Forest (Part beneath Vallis City) hidden behind a ledge and grass,
Lake Brevis behind the Brevis Cave, Route 7 blocked off by rock smash, Route 8 a little to the right from the small Duplex Hideout behind some water,
Venoa Marsh, close to where the Tame-Flower was found, Route 11 entrance to the Saltu Jungle, Route 13 close to Nanu Town blocked off by Rock Climb,
Goldvic Town (Pokémon League) close to Victory Road you have to surf
After encountering Zygarde go back to Tribus in Flopetal where he will hand you the Vitado Ticket.
Dive
You will find Kan in his house in Imperia City - Suburbs where he hands you the HM Dive.
Groudon, Kyogre, Rayquaza & Rematcher
Meet Alexo in his office in Imperia City and you can decide if you want to challenge Kyogre (Blue Crystal) or Groudon (Red Crystal) first.
For Kyogre head with the Blue Crystal to Lake Brevis inside the Brevis Cave where you can dive down and encounter it inside the Coral Fortress
For Groudon head with the Red Crystal to the Igno Vulcano and in the fourth room there is a strength stone to the left
which will lead you to the Magma Fortress.
After encountering each of them head back to Alexos office where he would like to meet you again at the center of Lostor Forest (the big part).
However he will only ask you if you obtained the Weather Orb from Marv. (Look at Yveltal, Xerneas & Weather Orb
If so you'll place the Weather Orb on the mossy stone and Rayquaza appears, ready for battle.
After encountering Rayquaza Alexo will give you the Rematcher.
Rematches against Gym Leaders and the Elite Four
After obtaining the Rematcher from Alexo you can now rematch every Gym Leader in any order you like.
After defeating all eight of them you can head to the Pokémon League and face rematches against the Elite Four.
Kyurem
Found south to Nanu Town inside the Ardus Grove which was blocked off by an old man before.
Darkrai & Cresselia
Someones missing in front of the old mansion at the Tritanium Plateau. The little boy broke in and you have to get him out of there.
Talk to his sister then break through the door and follow him through the rooms until you meet Darkrai in the upper floor.
After escaping the little girl hands you the Lunar Wing.
Then during night time head with the Lunar Wing to Lux Glade and encounter Cresselia.
Arceus
ATTENTION: This happens before the Post Game and cannot be done without further instructions:
You have to press a button inside the Duplex Headquarters in Pedraco City which activates a secret way inside the last room before Ilans Loft.
It leads to a painting behind some plants which you can examine and find the Azur Flute.
With that you can head to the top of Mt. Frigu and challenge Arceus there.
You can only enter Mt. Frigu after challenging the League once.
Flopetal Island & Vitado Island (Mew/Mewtwo/Entei/Suicune/Raikou)
After obtaining Dive from Kan and the Vitado Ticket from the Professor you can now head to Flopetal Island where you land in the village of Pavilla Ville.
There is the Scout headquarters located where you will be tasked with encountering a cookie thief (Mew) inside the Konterra Cave, to the west of the city.
After that you can head to Ventosa Town on Vitado Island where you will receive a key to the old lighthouse after listening to a story of an old man.
He sits next to the new lighthouse. Inside the old lighthouse talk to the statue and either Entei, Suicune or Raikou will appear.
Choosing Froakie as your starter, you'll encounter Raikou
Choosing Fennekin as your starter, you'll encounter Suicune
Choosing Chespin as your starter, you'll encounter Entei
Then head to Cape Fin up north and meet Tribus for a last battle.
After defeating him you'll obtain Mewtwo and you'll finish the game story wise now for 100%
