Valdimar is an interesting and capable Housecarl/Follower. As a Spellsword/Sorcerer, I often come to my Winstad Manor home and find him either walking away from Ustengrav with a mage armor spell active on himself and sometimes some blood splatter on his armor, showing that he just took care of the local bandits camped outside of the aforementioned Nordic Tomb.
Other times I have been hanging out at my Windstad Manor (specifically while I was building it), I would hear the sounds of magic being thrown around (such as Ice Spike/Icy Spear) flying around into trees, into myself or my followers, along with the occasional arrow or other Firebolt (as one of the respawning bandits is a necromancer mage). I would always have to find where all of those projectiles were coming from and usually would help him clear them out.
With my Steward being Brelyna Maryon (one of the three mage followers from the Mage's College), I now see them both coming back from that area with a mage armor spell active, as well as Brelnya's own Frost Atronach following her (as she is a skilled summoner).
It's things like this that make Skyrim fun, even without mods. It's one of the reasons I suggest new players to the game to play it without certain mods (armors, weapons, etc.) so they can see how the game is on its own. It is a work of art that stands on its own.