In theory this could also throw up some confusion about the power of Julius Caesar in the series up until now, but the series is not his story but rather that of the two Gauls. As a result, this is the tale of the ordinary soldiers' involvement in a wider conflict, rather than a grander fictional version of the war. The other big liberty taken is the presence of foreigners as legionaries, when in reality they were restricted to Roman citizens. Although some of the recruits are from within the Roman Empire, others, most notably the Goths, are from outside whilst Asterix and Obelix's own status is ambiguous (though this is more of a plot point in later stories). The result is a multi-national team of Gauls, a Goth, a Greek, a Briton, a Belgian and an Egyptian, making for a motley crew who prove utterly uncontrollable.
Much of the story focuses on the training and journey to Africa, with the actual civil war being largely a convenient conflict to provide a motivation for the recruitment and search. Asterix and Obelix largely wander into the legion when they set out to rescue Tragicomix, the fiancé of Panacea, a young woman from their village. Obelix has fallen for Panacea in a somewhat cliched sequence but shows his honour in immediately setting out to rescue his rival rather than seeing the impressment as an opportunity. However, what he and Asterix hoped would be a simple rescue mission from a training camp turns out to be a much longer quest when the military bureaucracy eventually reveals that Tragicomix has already been shipped out and the only way to follow him is to enlist.
The romantic side of this story is another light element that ultimately functions as a simple plot device to give Asterix and Obelix a quest rather than making it an exploration of how infatuation can drive a person to do anything for another's happiness even if it means rescuing a rival and denying one's own chances. This again shows up the influence of the French Foreign Legion genre where enlisting men are expected to have put their past lives behind them and not dwell upon their sweethearts. Even though our heroes have no intention of staying around once their mission is complete, the story still follows the pattern of a military recruit comedy.
The scenes in training show how order and discipline can so easily fall to pieces when respect hasn't been earned. Asterix and Obelix are eager to get to north Africa and do whatever they can to speed things up and improve conditions without regarded for the broader plan. Other legionaries have their own interests, whether in having a good time or financial advantage, and won't buckle down easily either. And there's a running joke throughout the whole story as Ptenisnet, an Egyptian, thinks he's found an inn and been taken on a holiday expedition to a camp, never realising he's been recruited into the army and the interpreter is ordered not to tell him. There's quite a bit of humour derived from the language barrier as both the Egyptian and Goth legionaries cannot understand the language directly, leading to some hilarious exchanges involving officers and trainers.
The art in this story has an extra task in making both Panacea and Tragicomix look stunningly attractive to justify the instant reactions and in this Uderzo succeeds well. He also has the fun of drawing two identical forces at war with one another that really emphasises the confusion and division amongst the Romans, best shown when Scipio orders a retreat only to find both sides' trumpeters are in the same spot. However, the nature of a suddenly divided civilisation and the conflicts it throws up aren't really explored beyond some jokes about everyone being confused and unable to tell one side from another, making for an utterly chaotic battle as nobody knows who to give orders to.
This story as a whole ultimately feels rather light. It has a clear structure, direction and purpose that serve to pull the narrative forward, but it just doesn't feel particularly filling - it's more like the initial army rations served rather than the better food cooked up after Asterix and Obelix have had words with the cook. There's no particularly awful moments or overlong dull sequences, but it just doesn't manage to excite too well.