It was more pride than hatred that led them here.
Demon Lord Kirgil is the strongest Demon Lord of the Rastrikan Demons that could even be comparable to the likes of Elder Tilrith, or at least he believed he was comparable, and thus the pride dwelling within him is overwhelming.
Finding that the others wanted to join was disdainful in his eyes.
No matter the enemies hunting them, it was their role to always come out on top in triumph.
Losing is not an option, it was a foreign word for them as a whole.
Also, celebrating or basking in victories against other forces should be a privilege reserved for other factions in the world. However, for the Rastrikan Demons, it was a different thing entirely as they considered themselves better than others.
Triumphs require no celebration, as such outcomes are simply expected, especially in this new era.
Due to this mindset, their reputation soared in ancient times.