Zanza doesn't want the future to change because the destruction of the world will keep him alive and is a part of the cycle of death and rebirth he set.
Jack doesn't want to change the future because of what he believes
Oh and here's the Monado
Item: Monado
Spoiler
Game of Origin: Xenoblade Chronicles
Power: Grants the wielder foresight and the ability to change the future through specific abilities.
Weaknesses: Can't Harm People, Apocrypha (Giant generator that disables the Monado)
Appearance:
Spoiler
Characteristics:
Originally posted by wiki
The Monado is a powerful energy blade that can manipulate the ether around it, and with it, change the material and immaterial shape of the world. The use of the Monado depends on the will of its user; most Homs who try to use the sword cannot control it. At the beginning of the game, the Monado cannot harm any Hom from Bionis.
The Monado grants its elected wielder the power of foresight. It is said that foresight is possible because all of the ether in the world is calculable in its changes. This allows the user to see where every ether particle is, was, and will be.
The Monado emits a particular ether wavelength in its ground state that attracts Telethia. Also, the Monado can be counteracted by using opposing particles of the ones the Monado uses.
Notes: The first known Hom wielder of the Monado, Dunban, was able to somewhat control the sword and use it as a weapon against the Mechon at the Battle of Sword Valley. In doing so, he was able to thwart an attack against Colony 9. Due to sheer discipline and strength he could wield the blade, even though he could not fully control it. Dunban unknowingly sacrificed the use of his right arm for victory in the battle against the Mechon.
Notes 2: Harbors the soul of Zanza.
