Sometimes, the attack of the Martial Body Sect can be as small as a harassment attack to test their defenses or frustrate them. As long as they can stand their ground and show that they won't be easy to take down, the attack of the individual groups of the Martial Body Sect will end as harassment.
The more severe attacks by individual groups usually occur when the Martial Body Sect senses weakness. If this kind of attack occurs, there will be a lot of casualties on both sides, and a city might fall.
The harassment attacks occur once a month, while the severe attacks can occur once every six months. At least, that's the usual frequency of attacks before Loki arrived on the battlefield.
For some reason, the city wasn't attacked for three months. Greg claimed that this was because the death of the rank 4 captain who ambushed him had rendered the Martial Body Sect without personnel to spare for an attack for some time.
