She is actually one of the best as she has 3 venom blade attacks on the charge for 10pts, that's a bargain! The simplest way to make her more viable would be to make agonisers count as poison weapons, or let her poison special rule affect her whole squad. Or even better make the archon's court 0-X rather than 1-X for the choices.
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Latest Report: BR4: The Repugnant Ramblers Vs Imperial Knights - 1250pts
Pragmatic Realspace Raider Series
“Even the Black Buzzards thought highly of him, and those maniacs were renowned for hating everyone.” - Tantalus, by Braden Campbell