The Talon of Horus

This causes Terror against all Imperial Forces, except for Blood Angels who gain Hatred

Troops who hate their adversaries take any Break and Rally tests with a Leadership of 10.
May re-roll any attack dice when they first attack in close combat against their hated foe.
Troops in close combat who hate their enemy must always use their 2" follow-up moves to get closer to the enemy or to engage another hated foe in close combat.

See rulebook page 66- too long to describe