Deadly Stalker (3.5e Feat)
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Deadly Stalker [Favored Enemy, Death Attack]
You specialize in your assignments on certain enemies.
Benefit: You can add your favored enemy bonus to the DC of your Death Attacks. In addition, you lose your Assassin spellcasting. Instead each Assassin level advances your Ranger spellcasting by one level, and you add the Assassin spell list to your Ranger spells. You use either the Assassin or the Ranger spells per day table, whichever is more beneficial to you.