[quote=@demonspade64]
<Snipped quote>

Wow highschool DxD already beat me to the punch, also i was going to make it a unholy weapon seeing how it kill the the son of god.

 
[/quote]

IMO, the fact that the spear touched the blood of God should turn it into a holy weapon of the highest order, then there's also the fact that St. Longinus killed Christ in an act of mercy, death by having your heart impaled in much quicker and less painful than withering at a cross for what could be anything between a few hours and almost a week depending on how strong the victim's body was.

That's what always makes Longinus be a holy weapon in any incarnation of it.