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It is unclear to me, even after reading the codex over and over, what creatures are effected by this and which are not. All it says are tyranid "broods" so does that just mean hormas/gaunts/raveners cuz they have the word brood in it? I cant imagine a fex needing to roll to see if it can move or anything.
I know not what weapons World War 3 will be fought with. All I know is that World War 4 will be fought with sticks and stones.
All tyranid units are called broods, not units like other armies call squads. Therefore ALL tyranid units are subject to Instinctive Behavior.
Genestealers and biovores are exempt per their rules of acting like a normal unit.
Synapse Zoe's, warriors, broodlords and tyrants are obviously exempt because they are always in synapse range.
Rippers, carnifexs, spore mines and lictors still must test for instinctive behavior, but are fearless, so they always pass their IB test and can move normally.
Hope that clears up any confusion.
FAQ rewrote a bit of the IB rules. Now any unit that is Fearless does not follow IB b/c it's written expressly in the rules.
So as the previous poster said, all units follow IB, unless they are Fearless, Synapse, or have a special rule in the unit profile expressly says they don't use IB. (i.e. brood telepathy)
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