According to the Cilpar resistance leader Elscol Loro, Moff Tascl was negotiating to hand over Imperial facilities to the Rebels when news of the death of Emperor Palpatine arrived. He then began attacking the local resistance. Tascl was dressed like an Imperial colonel. Tascl personally lead a ground attack on Rogue Squadron and their resistance allies from an AT-ST, but was eventually defeated and captured when his base was overrun.
"Boren" is Dutch for the verb "drill".