Runeforge Champion — ruling 1

Runeforge Champion's last ability provides an alternative cost to cast Rune spells. You can't combine this with other alternative costs that may apply. In the unusual case that a Rune spell has additional costs, you can pay those in addition to the {1}. If those additional costs are mandatory, you must pay them in order to cast the spell.

Runeforge Champion — ruling 2

Runeforge Champion's last ability doesn't change when you can cast a Rune spell.

Runeforge Champion — ruling 3

Casting a Rune spell for an alternative cost doesn't change its mana cost or mana value.

Runeforge Champion : règles, fonctionnement et interactions (MTG)

Runeforge Champion 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

When this creature enters, you may search your library and/or graveyard for a Rune card, reveal it, and put it into your hand. If you search your library this way, shuffle. You may pay rather than pay the mana cost for Rune spells you cast.

How it works : Runeforge Champion

Original English text — Wizards of the Coast / Scryfall

#1February 5, 2021· Wizards of the Coast
Runeforge Champion's last ability provides an alternative cost to cast Rune spells. You can't combine this with other alternative costs that may apply. In the unusual case that a Rune spell has additional costs, you can pay those in addition to the . If those additional costs are mandatory, you must pay them in order to cast the spell.
No other card is named in this ruling.
#2February 5, 2021· Wizards of the Coast
Runeforge Champion's last ability doesn't change when you can cast a Rune spell.
No other card is named in this ruling.
#3February 5, 2021· Wizards of the Coast
Casting a Rune spell for an alternative cost doesn't change its mana cost or mana value.
No other card is named in this ruling.