Lind was leading an auditorium of young Immortals. It was not only Frey Clan members but those that were allied with them. In exchange, they got resources and some support in the Endless Peaks.
Despite what the older powers might think, the Frey Clan had long known the Fiends were not the only enemies of their plans. Humans and demons were fighting for resources, space, and opportunities like everyone else.
The odd thing about Lind's lecture was the diversity of his crowd. Humans, demons, and aether children were fairly normal. The occasional beast in human form was also not too far outside the norm.
However, there were 2 more races that shocked other powers to their core.
Elementals were notorious isolationists. Despite the similarity with aether children, Elementals fundamentally distrusted other races after many tragedies. The few alliances they had were forged over billions of years.