Talk:Where the Sun Cannot Reach/@comment-28209103-20161020181459/@comment-27971189-20170505062007

In lore, Kiritsugu said "use it as my usual attack" and "You already see it". Meanwhile, the art focused on the knife, while you can see the knife emits black aura.

The only weapon Assassin Kiritsugu use for his usual attack is his knife. So yes, the knife is the "legitimate second NP" he's talking about. His first is Chronos Rose, which may count the Origin Bullet as a part of it.

On both F/Z and FGO, Kiritsugu save Origin Bullet for worst case scenario, so it won't fall to "I use it as my usual attack".