Rising Bane

(She never does name it, does she? I can make something up then)

Weapon (Sword)

A somewhat ornate sword which has two button-like caps near the crosspiece (hand guard). On release of these caps, (depending on the cap) the sword either lights on fire or lets the wielder telekinetically control plants. (It's really freaking obvious in the text)

A light, strong metal probably somewhat like this one that I read about at some point: https://phys.org/news/2015-12-exceptionally-strong-lightweight-metal.html
Because, I mean, the Narrator made it from nothing so technically it could be anything. The hilt is gilded and looks fragile, but it's not really. A solid sphere of metal rests as the counterbalance; the sphere could be a different, denser metal so to not stick out abruptly from the rest of the body of the weapon.

European style swords in general are not actually all that heavy--despite common misconception--and usually don't weigh more than 4 pounds. Since this one is generally lighter it's probably more like 1.5 pounds or at the most, 2.

Ability when triggered correctly to catch on fire or telekinetically control plants.

I still need to make the Narrator (the creator of the weapon and just about everything else)