Owen Bertram didn't remain idle in the rear. He requisitioned a training ground of the Flying Bear Army and used arrays and talismans to strengthen and modify it. Then he threw the three Red Barbarians in and let Leroy Baker and the others take turns to conduct "training". This training was later extended to the senior officers of the Flying Bear Army.
The Red Clan's Evil God mystic arts were strange and vastly different from the Cultivation Methods of the Wood Dynasty. It was somewhat better for the Flying Bear Army, as they were fighting against the Nanni Nation, whose people cultivated similar lower-level Evil God mystic arts.
Leroy Baker, Greystone, and some other cultivators had no experience in fighting against the Evil God mystic arts, so Owen Bertram arranged for special training in advance for fear they might suffer losses later.