This ability helps you accelerate towards transforming Sheoldred into The True Scriptures, a powerful Saga that can steal everything from everyones graveyard for yourself
Rather than try to use Nykthos as a Turn 3 mana boost, this deck uses it fairly as a way to power through on Turns 4, 5, and 6
The regular version of Bloodthirsty Conqueror even makes a reference in its flavor text
BLADEHOLD WAR-WHIP The top five of the year are largely interchangeable, and to say that any one of them is better is obviously just my opinion, but also heavily depends on the type of deck youre going to put them into
Those cards are considered to be "used to craft" that permanent as long as they remain exiled and the permanent remains on the battlefield, even if the permanent's controller changes or some of its characteristics change (because of a copy effect, for example.) If the materials required include multiple objects, you may exile some of them from among permanents you control and the rest from among cards in your graveyard

Brawl Legal Vintage Legal Timeless Legal Commander Legal Pauper Not Legal Oathbreaker Legal Penny Not Legal Toolbox Buy This Card Notes and Rules Information for Mammoth Bellow: Harmonize [cost] means You may cast this card from your graveyard by paying [cost] and tapping up to one untapped creature you control rather than paying the spells mana cost, If you cast this spell using its harmonize ability, its total cost is reduced by an amount of generic mana equal to the tapped creatures power, and If the harmonize cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack. (2025-04-04) Tapping a creature wont reduce colored mana components of harmonize costs