Yes, good question... and I have something else to pound about :
She turned to the side, numbly realizing where she knelt. The pool glowed beside her, just inches from where Elend had fallen. Some of his blood had dribbled into the pool, though it didn't mix with the liquid metal.
To be found on p.569...
Tell me this is not interesting. And don't forget about all those broken potery pieces. Elend has a whole one in his hand right now. What I see, here, might have happen with Rashek as well. Remember what the Steel Ministry taught those nobles ? That they had the gifts of Mistborn because they helped TLR at the beginning ? And why do I post this here ? Blood into the liquid metal, that's why. Let's picture this.
We are in Rashek's days. He doesn't trust any feruchemist anymore, worldbringer or not. He can hardly trust the Terris people either because they are responsible of the spreading of the "modified" Terris religion. One of the things that happen when a religion spreads, it that it makes converts. And somehow, Rashek surrounded himself with those. They were looking for a savior and here he is. He knows everything there is to know about the Hero of Ages, so he makes certain he fits the picture and those poor people (he despised them mind you) follow him blind folded. They all come to the Well but then The Mist Spirit does not want Rashek to fight against the Well's power, because he is not THE Hero. So he does what he did with Vin and Elend. He slashes open the bellies of all those followers... and their blood drips into the Well. Rashek is torn. He has to have followers, but the Well is there with its powers. If he takes it, can he not "redo" everything. So like Vin, he hesitates only a moment before entering the pool. As the liquid metal and all the blood drips of the people gets in him, he discovers the real power. Thanks to his blood bath, and to the metal he has ingested, he becomes the first Hemalurgist, maybe the only one if it is through hemalurgy that he creates the Inquisitors and the Koloss (maybe the Kandra, as long as we do not find metal in them under a form or another, I question this). He will keep the power and recreate everything. When he gets out of the Well, he sees the Mist Spirit and understand, somehow, that the use of those beads will help his dying followers. So, in a hurry, he brakes as many potery he can find and gives the beads to the people. They all become Mistborn. The power is pure. The Lord Ruler does not create Mistborn, but let's say that he acts as a wise woman. Then he may create whatever he wants or he did already.
When the Mistborns heals he makes them believe they owe their lives to him, and that he has blessed them in a way only a god can do. They believe him. He might not have told them not to mix with other people then, other people meaning those that are not Mistborn. He might have learn overtime that this dilutes the power and afterwards, he forbeeds them to reproduce with "lower borned" people.
Plausible ?