This is my prediction of Ash and his interaction with and battle against Wulfric.
Since he the last Gym leader before the Kalos League, I feel he needs to be very special. First off Ash and gang will meet him in the Pokemon Village, without actually finding out he's the Snowbelle Gym leader, showing his kindness for pokemon, some suggest this but maybe Ash will finally get his 6th capture here, my hope is probably a Phantump, and Wul will show his power through his mega Abamasnow through beating Team Rocket, then seeing Ash's own love for pokemon like him and learing of him planning to challenge the Snowbelle Gym, ask him for a battle with just his Mega Abamasnow, which would wipe Hawlucha, Talonflame, Noivern (who would evolve while watching Talonflame and Hawlucha lose) Pikachu, then Greninja(non ash-greninja). While commenting that Ash has amazing pokemon, also advises that he must be ready to strong and kind with them, especially Pikachu and Greninja, along truly put everything he's learned on his journey from past to present (from Kanto to Kalos) into his battle to truly be a match for the Snowbelle Gym leader and stand any chance of of have a strong chance to win the Kalos League and challenging Diantha, something Ash will take to heart and use to strengthen himself and his pokemon for his Snowbelle Gym battle, then Wul takes off with Ash not realizing that he was the gym leader.
Then once arriving at Snowbelle and learning that Wul was the gym leader, plus some other things I'll need to think about, he and Ash will have their gym battle, a six on six two episode gym battle with an audience. He made it like Juan's, round one is a double battle, then round two will be the usual one on one with their remaining pokemon, to truly test Ash's readiness to challenge the Kalos League. His Pokemon: 1. Castform 2. Walrein 3. Wealvile 4. Froslass 5. Avalugg 6. Mega Abomasnow
1.Hawlucha 2. Noivern 3. Trevenant 4. Talonflame 5. Pikachu 6. Greninja -- Ash-Greninja