The Roblox sword gear most likely being referred to is the Sword of Light , which has a “Time Change” ability that makes a white beam reach the sky and turn it daytime.

If you meant the colored sword series instead, the Periastron gears are the other big Roblox sword set people usually talk about, but those are known more for themed colors and combat effects than changing the sky itself.

What changes the sky

  • Sword of Light : changes the lighting/daytime effect with a beam to the sky.
  • Periastron series : a family of color-themed sword gears, not the usual answer for sky-color changes.
  • Custom sky/color-changing methods : some videos and scripts show sky-color changes through graphics or game-side effects rather than a standard sword gear.

Likely answer

The best match is Sword of Light.

Small note

Some Roblox communities also mention dynamic lighting gears or visual mod methods, but that is different from an in-game sword directly changing the sky.

TL;DR: the sword gear you’re probably thinking of is Sword of Light.