I was working on building a Zorro character and this question came up: if a rogue is riding on a mount, is that mount considered an ally, or, specifically, an "enemy" of your target?
One of the ways Sneak attack can be trigged is…
"… if another enemy of the target is within 5 feet of it, that enemy
isn’t incapacitated, and you don’t have disadvantage on the attack
roll."
My assumption is yes. Every mount I'm aware of has some kind of attack at its disposal, and thus they represent a threat to your target in addition to the increased threat potential they grant you as the rider. Moreover, if a gnome can proc a sneak attack by acting as a distraction, I don't know why a warhorse wouldn't be able to. That said, is there anything in the books or elsewhere that defines what "enemy of the target" is allowed to include?
Best Answer
If a word is not defined in the rules it takes its normal English meaning. Enemy is someone who is actively opposed or hostile to someone or something; in the context of a combat I think that they are opposed to you in a mortal combat sense rather than, say, holding differing political views.
On that reading, yes, your horse is an "enemy of the target". So is a familiar, or a guard dog etc. being able to actually harm the target is irrelevant.
I personally believe that it's should be easy for the rogue to get sneak attack. That is their schtick in combat and what makes them competitive with the tanks and spellslingers.