This question already has an answer here:
In The Last Jedi, we see Snoke has 8 guards with red armor in his throne room.
They are, obviously, similar to the Emperor's Guards from the Original Trilogy, who were (if I recall correctly) highly trained baseline humans. They were not Force-Sensitive, Dark Jedi, or anything similar.
They carry weapons which are capable of blocking lightsabers (which isn't novel in the First Order, as we have seen 'normal' First Order Troops with similar weapons) and are well-trained in their use.
When we do see them in action
Against Kylo Ren and Rey, after Snoke dies
they are able to fight effectively against trained, lightsaber-wielding Force users
Wounding Rey and battling Kylo to a standstill until he got support.
Outside of being well-trained and well-equiped, was there anything special about these guards?
Were they the other students Kylo took with him from the Temple Massacre?