Command Word (3.5e Flaw)
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You have a secret command word, known to yourself and your creator, that forces you do the bidding of whomever speaks it.
Prerequisite: Must have living construct or construct type.
Effect: When someone speaks your command word, they can order you as per the suggestion spell (8th level caster), but without the need to sound reasonable or convincing. You can never be ordered to directly kill or harm your creator, yourself or the person who spoke your command word. Only one person can speak your command word at a time, in a group the first person to say it gains control and maintains control for the duration of the effect.
Special: You are constantly aware of your command word and are free to tell it to anyone. Additionally, the detect thoughts spell, or any similar effect, can detect this word as it is constantly in your surface thoughts.