Thor
(Before Ragnarok, Odin had said, “Asgard is not a place, it’s a people.”)
(What Odin hadn’t anticipated, though, was Thanos.
The people are gone now, too.)
Thor might have lost more than any other Avenger. He’s lost his father, his brother, and his people, all in the span of a few weeks.
Still, Thor sees that Tony’s sorrow goes deeper than his own.
So, yes. Thor lost his father, his brother, his people. But Tony lost his child, and in the words of his mother Frigga, there is no greater pain than to outlive your own child.
And to watch your own child die, die because it’s far too late to save them, die because he was fated to by the snap of two fingers? Thor can’t imagine a faith more gruesome.
(After Loki had tried to kill Thor for a third time when they were young, Frigga had told him, “Do you know what they say, Loki, when a child is born? They say that a mother’s heart is then no longer her own. That it does no longer only beat for her, but also for her children. You will not kill your brother, Loki, for then, I shall only be a mere shell of my former self. And we both know you’d never want that.”)
(Loki stopped trying to kill Thor for a while after that.)