Doubles bodyguard

Mienshao @ Focus Band
Ability: Inner Focus
EVs: 252 HP / 4 SpD / 252 Spe
Jolly Nature
- Fake Out
- Wide Guard
- Quick Guard
- Ally Switch
Priority is important for a bodyguard. To preempt your opponent, all moves in this build have either +3 priority (Fake Out, Wide Guard, Quick Guard) or +2 priority (Ally Switch).
Speed is also maxed because you still need to outspeed your opponent if they use an equal-priority move. Fortunately, the only truly offensive move with priority +3 or higher is Fake Out. Unfortunately, Fake Out is common in doubles. Moreover, the ally Pokemon that can best benefit from having a bodyguard are particularly sensitive to losing a turn / timing advantage since they typically depend on setup (e.g. Geomancy Xerneas, Trick Room Calyrex-Ice, Dragon Dance Necrozma-Dusk, etc), momentum (e.g. incremental speed control, Beast Boost Pheromosa, Swift Swim Barraskewda, etc), risky HP management (e.g. any Focus Sash build, Endure Cramorant, Salac Berry Kommo-o, etc), and/or surprise (e.g. Air Balloon Regieleki, Final Gambit Victini suicide lead, Storm Drain Gastrodon switch-in, etc). Thus, this bodyguard build is designed to protect its ally from even faster Fake Outs earlier in the game at the cost of extra bulk to survive later in the game. After all, this Mienshao's ally should be powerful enough that their protection early on is more valuable than this bodyguard's survival later on.
Inner Focus functions as a fail-safe in case your opponent is still faster and decides to target this Mienshao with a Fake Out. (e.g. they are confident that they can KO your ally before your ally can attack) The more commonly-chosen ability Regenerator is not selected here because this bodyguard build is intended to stay on the field until you win or the bodyguard is KO'd (hopefully saving your ally Pokemon in the process). Besides, this build's defensive capabilities come from actively using its moves, not from pivoting and face-tanking attacks like a wall.
Focus Band is for surviving longer (i.e. for bodyguarding longer). The more commonly-chosen Focus Sash is not selected here because it is expected that Mienshao will suffer non-lethal damage before a Focus Sash would become relevant (e.g. from Electroweb/Snarl, G-Max Wildfire passive damage, a turn in which only one opponent was successfully blocked, etc.).