A lot of city folk's stereotype, to the point where in plays and theatre, it's one of the most common roles available to orcs, is the idea of an orc courier. The idea kicked off from a historical position where, out in the battlefield, Eresh nobles would pay orcs from nearby to deliver messages, because they were wholly independent, incredibly reliable, and unlikely to break promises. This was such standard practice that orcish communities would often check out battlefields and wars like it was a corner for work.
But this became enough of a thing at battlefields, that there were established relationships, that when knights and commanders headed back to the cities, orcs would commonly come along, and do long-distance courier work from city to city. If orcs were travelling the highways with messages on their own, like a mail service, often nobles would give the general some other notes, and thus began the pattern of a small number of orcs having this job. That led to more coming along to do it, because it's work they find easy (long distance travel under no pressure in return for convenient rewards at both ends of the travel).
This was long running enough that nobles started to hire them specifically, orcs formed loose unions, recruited non-orcs that could do the job, and language about the stereotype kicked in. It's a really persistent rumour that orcs are couriers because they can't read, so the message is secure. This is a really stupid stereotype, because the messages inevitably have their destination written on them and the orcs have to be able to read that.
The upshot is that 'orc messenger' is just a weird stereotype that the people of the Eresh Protectorate particularly hold to, because it's one of the ways that orcs show up in the cities most commonly... even if that archetype is so old that the Orc couriers founded Orc Courier companies, that are now just Courier companies and the city-living Orcs of the Eresh Protectorate do whole hosts of jobs. It's also even stranger that some people maintain the stereotype of an Orc as what we'd recognise as a Pony Express style courier, a lone wanderer on a horse with no roots and no friends, romanticised as an image under the starry sky, or as a terrifying highway plunderer. These two things seemingly exist completely indepdently in the head of idiots.
