That's actually a message from the (Arch) initramfs[1], in case it can't mount the root filesystem or find an init to hand off to.

The kernel has a different error message: "No working init found. Try passing init= option to kernel."[2]

1: https://github.com/archlinux/mkinitcpio/blob/2dc9e12814aafcc... 2: https://github.com/torvalds/linux/blob/d358e5254674b70f34c84...