Undead beings are like a plague; once they are truly set loose, they immediately spiral out of control, spreading indiscriminately and nearly unstoppable.
The Vanguard Armies arranged by Lind have infiltrated all three continents; however, considering that their secrecy is virtually non-existent, this "infiltration" could be seen as an outright invasion.
Other forces still don't know what they're up against, but for the Undead, the opening of a new game mode in their region is a cause for celebration, with many eagerly sharpening their blades to join the Black Knight Camp.
Conflict between camps has always existed; it's impossible for everyone to unilaterally join one side and abandon the other. So there are opportunists, as well as those who resist to the death.
This "PVP" battle has turned a world quiet for a full year back into an uproar, the fiery war engulfing every inch of land.