[ChainLegacy]

Originally Posted by Touko

That's what Zouken said, but he was obviously lying. We know Tokiomi's goal is to reach the Root (rather than achieving immortality), from several source. He was just trolling Shirou.

This is the part you meant, right?

Spoiler:

To give a daughter to the Matou family means giving us a foundation to achieve our goal. Tohsaka is well aware of that. We both have the same goals. We will both turn ourselves into monsters to achieve immortality."

"Immortality…?
You and Tohsaka's father used Sakura for something ridiculous like that…!?"

"Of course. The Holy Grail War has always been a ritual dedicated to that end. That is the only reason we cooperated, and I am the only one who still lives.
To use the Matou successor to achieve our goal in the far future."

And also, Zouken was lying in saying that the Ritual was dedicated for achieving immortality, while he knew its ultimate purpose was for reaching the Root.

I see. While I am not the most astute VN player, I find some of this information rather hard to surmise based on the in-game text. For instance, this 'root' was never properly described, in my view. Am I just bad at gleaning information, or are some of these concepts fleshed out more in related works (like Tsukihime, perhaps? I never completed the game)?