Horn Attack

When a Unicorn charges it uses its horn like a lance to pierce its enemy. This confers the same +2 strength bonus as a charging lance, so the Unicorn has a strength of 6 when it charges into combat.

Magical Protection

A Unicorn radiate an aura of magic power that can nullify the effect of other magic.
If a spell is cast against the Unicorn rider, or a unit he is with, then it is automatically dispelled on the D6 roll of a 4, 5 or 6. A dispelled spell has no effect.

Daemon Aura

A Unicorn's magic power extends to its attacks, shrouding it in magic. This disrupts the daemonic aura of a Chaos Daemon and cancels out its daemonic saving throw in the same way as a magic weapon.