"Up to a point I was very fit… until death set in. Death is inclined to undermine one's fitness." (1.55)
Titus has a really deadpan sense of humor. Because he's dead. Get it? Ba dum tssshh. (Sorry, we couldn't resist.)
And then the phone rang.
And it was Mum to say that Dad had died. (2.12-2.13)
Sym spends much of the book trying to work through her feelings about her father's death, even as she's faced with the prospect of her own. Death is a near-constant presence for her.
The timing of the two things—Dad's death, Oates's arrival in my head—suddenly tripped me up, and my concentration faltered […]. (10.39)
Sym describes her imaginary friend Titus as her love interest. But he's also a father figure who "came to life" on the same day as her father's death. It's probably best not to think too hard on the love interest/father figure thing.
"Still startling, though. In the end. When Death won't take no for an answer." (10.146)
Titus is often flippant when he speaks to Sym about his own death, but here he shows a more serious side. Notice that "Death" is personified here—it "won't take no for an answer" just like your mom.
Suddenly the lack of gloves made Bruch real again—flesh-and-blood real, not a character in a play, not an object of disgust, but someone who had given Sigurd his first acting job, his big break, his first script. (15.22)
Until they learn Manfred was poisoned, Sym and Sigurd assume he will die of exposure. Thinking of his uncovered hands is almost too much to bear because it makes his death seem all the more real.
"I've been easing him out of the picture ever since we left base camp! A little something toxic in every hot drink he drank. I just made the last one plenty strong." (15.26)
Victor's manner here is so nonchalant, he might as well be talking about the weather. Of course, he's not; he's talking about murdering Manfred Bruch. So it goes with Victor.
"I'll help you kill him, if you like," said Sigurd when I told him about Victor murdering my father. (18.1)
For a time, Sigurd and Sym plan to murder Victor. Ultimately, they're unable to follow through with the plan, though—murder isn't quite as easy as Victor makes it seem. Who'd've thought?
Maybe Victor's right! Never say die! If Victor's right, there's a chance we won't. Die, I mean. (19.62)
Spoiler alert: Victor is not right. But despite this, Sym does not die. Phew.
Dark takes him in the blink of an eye. (20.72)
R.I.P. Uncle Victor, who died as he lived: doing something super ridiculous, in this case, forcing himself through a crack in the ice. You do you, Victor; you do you.
"Ah! That's Death for you," he says, with a twitch of the nose, dipping his eyes in embarrassment. "Does wonders for a man's reputation, don't you know." (21.15)
One of the great ironies about (the real) Titus is that he was only famous in death. Had he survived his plight, no one would know his name.