Since Utgard tribe took that land, Yanlan could not rest easy.
This is because he knows that garron, the chief of Utgard is allied with Kazan tribe.
And Kazan chief always wanted to unite back the fragmented tribe into one.
Just like the Kazan wanted to unite the splintered Kazan tribe, Yanlan also wanted to unite the Kazan tribe.
Almost all of the chief of the splintered Kazan tribe all wanted to unify the splinter parts and become the true chief of the Kazan.
Hence, he has always pay attention to the area of that border.
There is not really a border that is pointed but there is the presence of Utgard scouts in that area.
Fearing an attack from that area, Yanlan put some of his warriors there to guard and to inform him if the Kazan suddenly attack from that area.
As for the north area, he did not put that much warriors to check that area.