problem of the darkening, wrinkled leaves. The plant was cut at the base of its stem and transplanted to proper cactus soil several months ago Furthermore, mentioning that new growth has been emerging from the top even as the lower leaves shrivel and dry up.
Dividing an Aloe is a great way to start plants, but people often neglect to let the end of the pup plant callous over. This step helps prevent the plant from rotting in the soil.
The darkening leaves are from root rot.
Keep moisture to a minimum.