Mandibuzz
-STAB attacks super effective against a few Pokemon in the Champion Cup, like Leon's Aegislash
-Weak to Melony, part of Raihan's Gym, and a few Pokemon in the Champion Cup, like Leon's Mr. Rime
-Heavily defensive
-Rubbish attacking stats
-Vullaby evolves late
-Learns moves like Knock Off and Foul Play
-Average Speed
Noivern
-STAB attacks super effective against part of Raihan's Gym, and a few Pokemon in the Champion Cup, like Leon's Haxorus
-Weak to Melony, part of Raihan's team, and a few Pokemon in the Champion Cup, like Leon's Mr. Rime
-Blistering Speed
-Solid Special Attack
-Learns moves like Dragon Pulse, Boomburst, Hurricane, and U-turn
-Noibat evolves late
-Merely okay HP and defenses
Corviknight
-STAB attacks super effective against Melony, part of Raihan's Gym, and a few Pokemon in the Champion Cup, like Marnie's Grimmsnarl
-Weak to a few Pokemon in the Champion Cup, like Leon's Charizard
-Excellent HP and Defense
-Decent Special Defense and iffy Speed
-Respectable Attack
-Learns moves like Brave Bird, Iron Head, Body Press, and U-turn
If you want a special attacker, use Noivern. If you want a physical attacker, go for Corviknight. Mandibuzz is defensively oriented and shouldn't be used in-game. Here's sets for Noivern and Corviknight:
Noivern @ Dragon Fang / Sharp Beak
Ability: Infiltrator
Nature: Modest
- Boomburst
- Dragon Pulse
- Air Slash / Hurricane
- Flash Cannon
Corviknight @ Metal Coat / Sharp Beak
Ability: Pressure
Nature: Adamant / Jolly
- Iron Head
- Brave Bird / Drill Peck
- Body Press
- U-turn
Hope I helped!