I've read a bit ahead in the novel. It's mostly beacuse they're all naturally gifted that they've always been treated with fear/reverence, and they started to plateau because nothing is challenging anymore. They're attachment and fascination with Ecrid is because
1) he was average and the next day (which is days or months later in Ecrid's time) he becomes much much stronger, so they get invested in how he gets so strong, and want to push past their limits too but also
2)he treats them like subordinates, which they are to him, but they rarely get treated like that. He respects them, but he also enjoys their company and treats them like a leader should even though he was weaker than them. So they respect and follow him in turn.

I dunno if I'm just really slow. . . I wanna ask a genuine question. . The "lunatic" squad members appears to be really attached to mc. . . Why is that?
Not that I have qualms with that. . .in fact, I'm loving it. . . But why is it so?