The Brothers' War — ruling 1

Powerstone tokens are a kind of predefined token. Each one has the artifact subtype "Powerstone" and the ability "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell."

The Brothers' War — ruling 2

You can use the {C} added by a Powerstone token on anything that isn't a nonartifact spell. This includes paying costs to activate abilities of both artifact and nonartifact permanents, paying ward costs, and so on.

The Brothers' War — ruling 3

Although all the cards in The Brothers' War that create Powerstone tokens create a tapped Powerstone token, entering the battlefield tapped isn't part of the token's definition. Notably, if you create a token that is a copy of a Powerstone token, the token copy won't enter the battlefield tapped.

The Brothers' War : règles, fonctionnement et interactions (MTG)

The Brothers' War is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Create two tapped Powerstone tokens. II — Choose two target players. Until your next turn, each creature they control attacks the other chosen player each combat if able. III — This Saga deals X damage to any target and X damage to any other target, where X is the number of artifacts you control.

How it works : The Brothers' War

Original English text — Wizards of the Coast / Scryfall

#1October 14, 2022· Wizards of the Coast
Powerstone tokens are a kind of predefined token. Each one has the artifact subtype "Powerstone" and the ability ": Add . This mana can't be spent to cast a nonartifact spell."
Card named in this ruling
Powerstone
#2October 14, 2022· Wizards of the Coast
You can use the added by a Powerstone token on anything that isn't a nonartifact spell. This includes paying costs to activate abilities of both artifact and nonartifact permanents, paying ward costs, and so on.
Card named in this ruling
Powerstone
#3October 14, 2022· Wizards of the Coast
Although all the cards in The Brothers' War that create Powerstone tokens create a tapped Powerstone token, entering the battlefield tapped isn't part of the token's definition. Notably, if you create a token that is a copy of a Powerstone token, the token copy won't enter the battlefield tapped.
Card named in this ruling
Powerstone