[Endoperez]

Generally, single weapon with Area of Effect is about as useful as huge number of attacks. The SC must use all of its attacks in the same grid square of enemies. If you don't know what I'm talking about, press 'g' while viewing a battle.

Because of the above, one of the one-handed weapons with Area of Effect (Fire Brand, Frost Brand, Shadow Brand) and weapons or shields with good special abilities are probably most useful. Resistances or immunities (from e.g. Scultata Volturnus), protective abilities (Charcoal Shield gives Fire Shield, Vine Shield will drastically lower the amount of attacks your enemies get to make against you) and perhaps an armor-piercing or negating attack (Duskdagger) if you're expecting enemy SCs.
All SCs want Luck and as high magic resistance as possible with as low Encumberance as possible, so you shouldn't go overboard with shields. Depending on what items you want to put on his other slots, you can increase his magic resistance with Lead Shield (which, unfortunately, is heavier than many armors) or give him Faithful the sword, to bring Luck.