Don't be a baby ttwesten. It doesn't need a reason you find "acceptable", let it run, let it thrive. I don't think I can support this taking up no magic slots given the loaded nature of a celestial (I'm looking at abilities), I also feel that it makes sense to take that additional slot due to further ""attuning"" to the void.
A word of advice, redlines for abilities under the abilities. It's very helpful to read and doesn't involve the reader having to cycle from the ability to the end of the piece to match the corresponding redlines.