オレが...ここにいることで生かしてもらってることはわかってるつもりです
Translation in the manga: I'm...here so I see you intend to let me live
tsumori means the person plans on keeping him alive? In another version it just says "I know being here keeps me alive."
オレ自身が人類の天敵たりえる存在であることも
Translation: I also see that I can be the natural enemy of humanity
In a different translation it doesn't say "also" but this sounds better, I think?