▲Destiny has ordained that they are who they are.

翻译：命运已经决定了他们的性格和为人。

▲who 的三种用法：

1. 疑问代词，引导特殊疑问句：Who are you talking about?

2. 连接代词，引导名词性从句：I don’t know who you are talking about.

3. 复合关系代词（也可叫复合连接代词）,引导名词性从句：

The woman is very rich now. She isn’t who she was. 这位女子现在很有钱了，她不是以前的那个她了。

▲作为复合关系代词，who 没有疑问的意思。它相当于the person who/that，who本身既充当了先行词，又充当了关系代词两个角色。

She isn’t who she was. 相当于：She isn’t the person who/that she was.

你的句子 Destiny has ordained that they are who they are. 直译是“命运已经决定了他们是些什么样的人。”意味着：命运已经决定了他们的性格和为人。

不过，who的这种复合关系代词的用法，较为少见，远不如what用得经常。例如：

What is in the box is an apple. (=The thing that is in the box is an apple.)

▲判断 who 是连接代词，还是复合关系代词，有一个规则请参考：一般说来，who 引导的句子如果跟“疑问，询问，怀疑，质疑，好奇，不知道，想知道，不清楚，不明白，不理解，不确定，悬而未决”等意义的词连用时，那么，who往往就是“连接代词”。反之，则是“复合关系代词”。

你这个句子My question is who will marry a poor man like me. who为何带有疑问的含义？因为有一个question作主语，结果如此。

▲Destiny has ordained that they are who they are.中，who是“复合关系代词”，那么，相当于Destiny has ordained that they are the persons that/who they are.