Tri-Tip Dagger

https://riskofrain2.fandom.com/wiki/Tri-Tip_Dagger

Trivia

 * Triangular knives or trench knives were knives created during the First World Wars. Their blades were often three-sided (or more) as a result of the forging process. Wounds caused by them are often described as "bleeding profusely" and "impossible to stitch". These are, however, just popular myths.