The Beast Mark of Death was identical to other Totem mystic techniques. It was achieved by killing a desolate beast, extracting the essence of life from it and merging that life essence into one's body. Previously, when Yi Yun killed the Golden Crow species, he had used the Beast Mark of Death to condense his Aspect Totem.
In fact, the "Myriad Beast Totem" remnant copy that the Tai Ah Divine Kingdom had only had the procedure regarding the Beast Mark of Death.
However, in the God Advent Tower, after Yi Yun obtained the complete "Myriad Beast Totem", he found another procedure to condense a beast mark, that was the Beast Mark of Life.
Under the situation of not killing a desolate beast, but condensing it into a Beast Mark of Life, the entire desolate beast's spirit, soul, Qi, and blood would merge with his body.