Skaffen-Amtiskaw, of The Culture series.
So deadpan delivery of unintended puns, so incapable of understanding the hows and whys of the human oddities and emotions. Loyal all the way to a fault and slightly beyond, and utterly uncaring of your wishes if it disagrees with them too much.
And must not forget, deadly as well. Intelligent knife-missiles for the win
For those unaware of the Culture firepower and technological capacity...
"The short story
A Gift from the Culture mentions a antimatter-powered handgun capable of firing 10^8 Watts of plasma. The protagonists reflects that he would be able to level the entire city around him, in the end opting for just shooting down a starship. The gun is officially rated as a general purpose 'peace' weapon, in other words not powerful enough for full battlefield use. Cheradinine Zakalwe, mercenary extraordinaire from
Use of Weapons, packs an arsenal of more capable arms."
And stats for one of their wars which didn't quite push the Culture to their limit in production capacity...
Idiran-Culture-War. Length of war: forty-eight years, one month. Total casualties, including machines and non-combatants: 851.4 billion. Losses: ships (all classes above interplanetary) 91 215 660; Orbitals 14 334; planets and major moons 53; Artificial Ringworlds 1; Artificial Sphereworlds 3; stars 6.