Waldo also had his own considerations.
Firstly, he genuinely wanted to confront the Zombie Lord in battle.
Secondly, Waldo was drawn to the Source stones within the Zombie Lord's head. The Source stones in the Zombie Lord's head were definitely of higher quality and quantity compared to those in a third-level zombie.
This greatly intrigued Waldo.
Lastly, regardless of the reasons mentioned above and various other factors, West City would be his home for a long time to come. He had to find a way to resolve this crisis.
Based on these points, and many other significant reasons, Waldo ultimately decided to step up and encourage all factions of City 25 to form an alliance army.
Thus, shortly after, Waldo released an announcement:
