As above, so below, is an important concept to Kabbalah. The Tree of Life is the above. The Qliphoth is below. It represents the deepest and darkest places of the human consciousness.
Here's a little introduction to Qliphoth.
If you apply Sumerian to Reverse Ordinal, you have the value of 666.
6 x Reverse Ordinal = Qliphoth = 666 (Reverse Sumerian Gematria)
It is also spelled Qlippoth, as opposed to Qliphoth.
Notice the '113'.
In understanding Gematria, we can understand why different groups would want to spell words different ways. Notice the 'Qelippot' spelling, which yields 47. Number of foundation.
Last, there is the 'Kelipot' spelling.
Notice the overlap with Jewish.
The term Sitra Achra has Gematra of '44', connected to killing, and this Tree of Death, is connected to evil. I think you see the parallels.
'Tree of Death' has Gematria of '55', like 'Satan'. Again, this is focused on the evil side of humanity.