Ya never heard of Squats!
[img]https://s-media-cache-ak0.pinimg.com/originals/6a/7d/47/6a7d47677172cd807b88fb1c6578c60d.jpg[/img]

or the Demi-urg (although those are xenos so kind of meh), both of which have rekd the Eldar in their history, with no reprimand from the knife-ears!
[img]http://vignette2.wikia.nocookie.net/warhammer40k/images/e/e5/Demiurg_or_Squat_by_Asurael_Returns.jpg/revision/latest?cb=20111006162531[/img]