Ulaks, similar to those found in the Riddick movies

Ulaks are curved single-edged knives with serrated edges typically used in tandem. ... Richard B. Riddick took a pair of these from a mercenary on-board the Dark Athena.

These "swingblades" are capable of slicing and stabbing positions, and are designed to compliment the natural motions of a person's arms and hands in close combat. The serrated edge is used for blocking other bladed weapons.

Source http://riddick.wikia.com/wiki/Ulaks

Once printed and assembled they are nearly 14 " long.