The dream of that man was pure. His wish was for everyone in this world to be happy; that was all that he asked for.
It is a childish ideal that all young boys grow attached to at least once, one that they abandon once they grow accustomed to the mercilessness of reality.
Any happiness requires a sacrifice, something all children learn when they become adults.
But, that man was different.
Maybe he was just the most foolish of all. Maybe he was broken somewhere. Or maybe, he might have been of the kind we call 'Saints', entrusted with God's will. One that common people cannot understand.
He knew that for any existence in this world, the only two alternatives are sacrifice, or salvation...
After understanding that, he would never be able to empty the scale plates...
From that day on, he set his mind to work on being the one to tip the scale.
(Fate/Zero, Prologue 1, Baka-Tsuki )