1 Kyros: Another Balrog overcome!
2 Lambert: You claimed to have killed them!
3 Kyros: It might be dead. You don’t know for sure.
4 Lambert: Dead of boredom from talking with you.
4 Kyros: Any effective weapon is a good weapon.

When you think about it, any effective anything is a good anything. Since the quality of being a good thing is being effective at what it's supposed to do.

Uh. So, in other words, Kyros just used a simple tautology as a punchline.

Any effective punchline is a good punchline.