Copium

Copium is a naturally occurring substance found throughout the world. When in gaseous form it is often used as a recreational drug alongside alcohol, caffeine, and tobacco. It also has certain medicinal properties.

Obtaining
While Copium's natural state of matter is gaseous, the substance naturally occurs in the form of small purple crystals deep underground or in large geode deposits on the ocean floor.

The crystal compound can be dissolved in water, resulting in the release of Copium gas and a slightly salty, albeit harmless, water.

Recreational
In its pure gaseous state, Copium is used to ease the mind, especially after moments of intense stress. Because of its depressant and euphoric nature, small amounts of copium are often integrated into day to day life.

Public baths have been known to dissolve small amounts of copium crystals in the water over extended periods of time to release the gas. It is also used in a more concentrated manner during sauna sessions, dissolved and released along with the steam.

In smaller amounts, the substance is also used in incense and air humidifiers. These smaller versions are often used at a person's desk or office.

Void Rockets
One day in early November 2021, Grand Marshal Karma was mining for Iron and Gold when he unwittingly stumbled across a more enriched form of Copium crystals. The Nekojin was also unaware of the magnesium deposit lining the rock, the metal commonly used in gunpowder. With one strike of his pickaxe, a spark ignited the magnesium which burned brightly. The intense heat caused the instantaneous combustion of the enriched crystals. The Copium exploded in a spectacular display of purple and black, nearly killing the marshal.

Upon further investigation, Karma discovered that the chain reaction of ignited magnesium and a more refined Copium substance was what caused the explosion.

During this time, Karma's nation of Rohel was dealing with the threat of war after war after war. The military general instantly saw a new use for the substance. At first Karma tried to make a more potent TNT... but it failed. The larger amounts of Copium required were often not fully used and thus wasted.

Thinking on a smaller scale, Karma went to work creating makeshift rockets for his crossbow. The first few attempts were failure but soon enough he had a working prototype which exploded in the same spectacular display of purple and black as that day in the mines.

The colors reminded the Nekojin of old stories about Endermen and thus named them "Void Rockets" after the very void dimension the creatures supposedly exist.