After 3 days...
8 kms west from Fernandes territory...
The Black force has been marching for days and they finally got rest. Donald was so eager for vengeance that he disregarded the well being of the Black force. Due to the long journey and some monster attacks on the way they lost 20 members.
Tiller, Bastion and Murdock were the three captains of the present Black force. Over the time they marched through the terrains and reached this place they saw the true face of Donald who did not care for the force and only wanted the troops to do as he says without taking advice from the captains.
When captains tried to persuade him over the wrong decision about marching over the night near werner cliffs on the way where monsters were abundant and the force was tired to tackle those monsters he did not take their words seriously which led to those casualties.