The two armies were not large - especially when considering that they were about to raid an entire realm. The entire population of that realm, according to the data Velma had collected, was around 3 billion.
Of that, there were around 600 million combatants, most of them in the mortal levels. Naturally, as the cultivation level rose their numbers dwindled, but quantity had its own advantage.
Apparently, the population of the realm used to be far greater, well over 20 billion. However, the realm had suffered from a prolonged war between countless tribal warlords, from among whom the Grand Conqueror had emerged. By the time he unified the realm, the population had dwindled severely.
This 3 billion now was a result of active efforts to regrow the population.
The Midnight Inn wasn't short of people either. Since they handled billions of guests, the number of workers naturally had to be increased.
