Main Weapon: Vampire Killer whip

The Vampire Killer is the legendary whip of the Belmont Clan, created during the events of Castlevania Lament of Innocence back in 1094. After defeating Dracula in 1999, Julius sealed it in the castle, but he recovered it during the events of Aria of Sorrow.

Vampire Killer
A whip that destroys all that is associated with the dark creatures of the night. As a result of an ancient blood pact, it can only be used by a Belmont. Its power was temporarily weakened last year when Soma broke free of his destiny as the dark lord. However, its potent power has not been entirely lost.
- Castlevania: DoS Library Entry

Subweapons:

Julius gets the usual arsenal of classic Belmont subweapons which he can switch between at any time.

Axe
An axe which is thrown diagonally.

Cross
A cross-shaped boomerang that travels across the screen.

Grand Cross
Julius summons a large cross in mid-air.