No.
Desecrate does not specify it grants that immunity. If it doesn't specify such, especially for a powerful ability like that it must be assumed not.
From a rules-balance issue, giving a 2nd level Cleric Spell a spell with a 2 Hour/Level duration (and a constant ability for the class in question) outright immunity to negative energy would be insanely broken. It would make them immune to Level Drains from undead, Inflict Wounds spell series, Harm, Destruction, Slay Living, Enervation and Energy Drain spells, and it would also grant immunity from Planar conditions of Minor Negative Dominant or Major Negative Dominant planes of existence.
In D&D 3.0 (and earlier versions) there was the Negative Energy Protection spell that granted such a limited immunity, but it was 3rd Level and didn't give outright immunity from all Negative Energy effects. In 3.5 they thought that effect was too weak for a 3rd level spell and too specific, and incorporated it into the Death Ward spell, which is 4th level Cleric & Paladin spell (also 4th level Death domain and 5th level Druid). Death Ward in 3.5 does give the complete, blanket immunity to all negative energy effects you are asking about, but it is only 1 minute per level. Death Ward in 3.0 doesn't grant such a total immunity, and is much more limited. |
