sword, dagger, saber
釼 centers on bladed weapons: a sword, dagger, or saber. The meanings are straightforward and refer to edged metal weapons.
釼 is a variant form of 剣 (sword). It combines 金 (metal) with 刄 (blade), clearly indicating a metal blade. The exact historical development of this particular variant is uncertain, but it likely arose as a way to emphasize the metal material.
The left side is 金 (metal) and the right side is 刄 (blade). Picture a sharp metal blade: 釼 is a sword or dagger.
For ケン, imagine a swordsman named Ken wielding a metal blade: Ken -> ケン, and his sword is 釼.