While I hadn't played the entire ruthless route [and I don't intend to, I just feel horrible for sending Asterion out for no reason], it's so anti-thetically opposed to what the good route has you do, and I find it poetic in a way. Once you send the minotaur into the valley, you're locked into the route regardless of what you do from what I could tell, and man, I appreciate how detached I could make myself from that act, for I never want to do that ever again. Giving the master a character of true cruelty really is a good way to describe the depravity of what this world can entail on someone, and it hits home very well: for anyone can turn into a wretched path, and all acts are done with selfishness in mind, but the ruthless route goes a step beyond that to showcase the true fatal flaw of humanity- the desire and capability to harm and torment someone for no logical gain aside from an emotional one.
I played the ruthless route, though a fitting name could be the depravity route with the sudden switch to sadism and primal thinking of the master. They, as I shall refer to them, make many villains seem like snowflakes in comparison: right off the bat you're assaulted with the consequences of your choice, even if just singular. I tried to be silent and mean without sending Asterion out, but to see that it is only THIS choice to determine the master's will is kind of horrifying to think about. The fact you can tell this isn't the true route of the game makes me happy, and it's like it could all just be a bad "what if" dream the player could be disgusted at, instead of the game's alt route alongside the main one.
It's a greatly written route, but I hate it with a lot of might to bite onto. To torture innocence for no gain other than sick sadism is one of the lowest points you can go to in any video game, IMO. Amazing work on the game, by the way. Each route, both ruthless and merciful as I will call it, do the themes justice, and I shall await with eternal patience for the day the finale is showcased. But alas, no rush in perfection.