Planet Forge, formerly called UX-13 I, is the lone planet in the UX-13 System.

Note that Forge is a high-gravity world. An average Nekovalkyrja, Type 33, who normally weighs 45kg (99lbs) would weigh 55.8kg (123lbs), for instance. Also note that things ignite and burn much more easily on Forge, due to higher oxygen levels (26.1% vs. Earth's 20.95%). The sunlight is red and not very bright, making things look dim and pink most of the time. It can get very hot on the surface. Normal trees cannot grow on Forge due to the lack of carbon dioxide.

Forge was colonized by the Yamatai Star Empire in YE 30.

In YE 36, this planet became part of the PAINT public transportation system and has a Tenba that regularly visits and provides passenger flights to Shinjuku Starport on Hanako's World. In YE 38, Trinary Star Shipping established a storefront on Forge.

In YE 41, planet Forge was conquered by forces from the Interstellar Kingdom Of Kuvexia during the Kuvexian Invasion of YE 41.

• A Frontier Starport, built in YE 33
• UX-13 Training Center (Fort Ready II)
• 500 Refugee Towns (closed in YE 36)

• Type Large iron/silicate

Radius 8436.58 km (1.32 x earth)

• Surface Area 8.94 x 10⁸ km²
• Land Area 5.01 x 10⁸ km² (3.36 x earth)
• Mass 1.30 x 10²⁵ kg (2.18 x earth)
• Density 5.17 g/cm³ (0.94 x earth)
• Composition 28.3% oxygen, 27.2% iron, 17.0% aluminum, 16.6% silicon, 8.4% sulphur, 1.1% other metals, 1.4% other elements

• Gravity 12.14 m/s² (1.24 x earth)
• Escape Velocity 14.31 km/s

• Period 22.57 hours
• Axis Tilt 21.25 °

• Water 45 %
• Ice 16 %

• Type Standard breathable
• Pressure 93.97 kPa (0.93 x earth)
• Composition 73.9% nitrogen, 26.1% oxygen, trace other gases

• Cool
• Min Temp 255 K (-17 °C)
• Avg Temp 295 K (22 °C)
• Max Temp 352 K (79 °C)

• Chemistry Carbon
• Lifeforms Prokaryotic microbes

• Large moon