[ He's suspicious, and not entirely taking this well. Marius is in two minds - one side of him remains loyal still, remains in fear of what he's becoming and in fear that he won't be able to stop it. The other side simply wants more ADAM. That base desire has overtaken him, making him distrust his friends and search for the very thing that caused his problems in the first place. ]

I fear I have already fallen. Courfeyrac, I know what it is doing to me. I can see the evidence on my skin and hear it in my voice, but I cannot stop it because there is only one thing that makes it stop.

The same thing that Enjolras, that Alayne, that you would keep from me.

Tell me I am wrong, and I shall argue with you no more.