Some help with the following dialogue exchange

Question

I'm attempting to translate the dialogue of a video game. I'm making good progress but there's a specific dialogue exchange I'm not sure about.

Some context beforehand (the section called ☆マクシームの城★) :

https://www49.atwiki.jp/aniwotawiki/pages/29947.html

Context related to the dialogue in question (I also included my own translations, so feel free to correct any mistakes):

ジュスト： 「．．．こんな所にいたか。 リディーを渡せ！！」

Juste: "So this is where you were! Return Lydie to me!"

死神：「案ずるな。あの娘は、マクシーム殿のところだ。」

Death: "Fear not. That maiden is now with lord Maxim."

ジュスト： 「何故！？　お前にリディーは関係ないはずだ！！」

Juste: "Why!? Lydie has nothing to do with you!!"

死神： 「あの娘は、この城を完成させるために必要な因子なのだ。」

Death: "Because that lady is an essential element for bringing this castle to perfection."

ジュスト： 「それはどういう意味だ！？」

Juste: "What do you mean by that?!"

死神： 「この城をかりそめの城として、我が主の復活に備えさせていただく。だが、２つの城を１つにしなければ、この城は完全とは言えぬ。つまり、お主の親友とやらの心に消えてもらう必要があるのだ。」

Death: "I have the pleasure of preparing this castle as a temporary castle for the resurrection of my Lord. However, if the two castles are not reduced to one, it cannot said to be perfect. In other words, it's neccessary for the spirit of your dear friend, or whatever you call him, to be erased. " 　

ジュスト： 「マクシームは強い男だ！そんな簡単に思い通りにはならない！！」

Juste: "Maxim is a strong man! It won't happen so easily as you think!!"

(Note: I'm really struggling with the bolded sentences)

死神：「我が主から生まれし者だ．．．。その力を増強させる方法を知らぬわでは有るまい。しかも、愛しいものなら、その効果は測りしれぬ。」

"(Lord Maxim) is one who is born from my lord. It's not like he doesn't know a method of increasing his power. And yet, there's no telling what effect your loved one will have (on him)."

「ジュスト： !?　ま、まさか．．．リディーの血を．．．。そこをどけ！！」

"!? N-no way... Lydie's blood... out of my way!!"

Video of the dialogue exchange (6:28 - 7:34)

https://www.youtube.com/watch?v=QVO2q0upiXM&t=435s

Answer 1

我が主から生まれし者だ．．．
(Maxim) is one who is born from my lord.

I see no problem with your translation here. Though it's worth noting that the "Lord" he's talking about is presumably Dracula. The point seems to be that Maxim carries Dracula's power within him.

その力を増強させる方法を知らぬわけでは有るまい。
I am sure you must know the means by which that power can be amplified.

Literally more like "Surely you cannot not know", but that sounds awful in English(!) Death is alluding to the well-known fact that Dracula draws his power from human blood, and thus implying that he intends to use human blood to draw out the power of Dracula within Maxim.

しかも、愛しいものなら、その効果は測りしれぬ。
And what is more, if (it is taken from) one beloved (to him), the effect will be unfathomable.

And here he specifies that the blood of someone Maxim loves (ie. Lydie) will be particularly effective.

Hopefully that clears everything up!