THE NAME the serpents and the wolf... Maybe it's because now many bad gladiators (serpents) will be able to take on a Big Bad Gladiator like spartacus (Wolf) in the arena!
Based on what I saw on the TV show, probably the expansion name comes from the house sigils (we saw these sigils on the two image teasers as well).
Seppius is leading a local milita in Capua and his sigil are the two serpents entwined. Varinius is a Roman praetor, hence the Capitonline Wolf sigil for his house.
So I guess the name refers to the two new houses (and the game can play up to 6 players now).