Lucid Dreamer
SS, p.67
defense against attacks in dreams

The Lucid Dreamer Merit is common among both ordinary people and psychics. It represents the capacity to realize that one is dreaming and that such dreams cannot truly cause harm. Your character is rarely troubled by any but the most terrifying of mundane nightmares, although he remains vulnerable to supernaturally or psychically induced ones. The Dreamer can defend himself against attacks by psychics who have the Dream Travel Merit.

When a Lucid Dreamer is psychically attacked within one of his own dreams, his Composure is considered to be +2 for purposes of determining whether a dream attack can harm him. Second, a Lucid Dreamer can initiate attacks against intruders of his dreams. One Willpower point must be spent per attack, and each attack is resolved according to the rules for Dream Travel described on p. 38. Unless a Lucid Dreamer has the power of Dream Travel, he can initiate these attacks only within his own dreams.