Details: One of the thirteen Special Trainers you will encounter at The Battle Tree after completing certain streaks with the multiple of ten in single player modes or team up with in multi-Battle mode is Sina, one of Professor Sycamore's Assistants from Kalos. She likes Ice Type Pokemon, but uses other Pokemon of varying types.
Possible Pokemon:
Sandslash (Icium Z): Hail, Icicle Spear, Iron Head, Aurora Veil
Abomasnow (Focus Slash): Blizzard, Sheer Cold, Focus Blast, Ice Shard
Abomasnow (Abomasite): Blizzard, Focus Blast, Protect, Ice Shard
Glaceon (Focus Sash): Hail, Blizzard, Mirror Coat, Hyper Beam
Glaceon (Bright Powder): Blizzard, Shadow Ball, Aurora Veil, Detect
Lilligant (Leftovers): Quiver Dance, Energy Ball, Leech Seed, Protect
Lilligant (Grassium Z): Solar Beam, Teeter Dance, Charm, Leech Seed
Mandibuzz (Sitrus Berry): Nasty Plot, Dark Pulse, Air Slash, Tailwind
Mandibuzz (Leftovers): Substitute, Swagger, Punishment, Roost
Oranguru (Mental Herb): Psychic, Shadow Ball, Focus Blast, Trick Room
Oranguru (Electrium Z): Foul Pay, Psychic, Focus Blast, Thunder
Drampa (Quick Claw): Hyper Voice, Dragon Pulse, Fire Blast, Roost
Drampa (Dragonium): Draco Meteor, Focus Blast, Hurricane, Glare