My Bodyguard is 4 Feet Tall

Gin is a tall private eye with a dangerous side project crafting potent drugs for mobsters. He's also an inept swordsman whose most powerful tool is... bluffing. Gin's about to get his butt handed to him when a short but deadly fighter named Ian rescues him with a ridiculously large weapon — just who is this shorty?! Despite Gin's best efforts to eject this annoying (albeit talented) kid from his life, danger knocks on their door. They've got big cases to solve and bigger secrets to discover.

(Source: Tapas)

Nite: Chapter count includes prologue.