I'm playing the last unstable version (not nightly).
I've managed to obtain all artefacts and opened the gate in the Ark Ruins and teleported to the Ruin (planet) where the final boss should be.
But how do I find him? I've tried to dig to the bottom of the planet and found nothing but a bottomless pit. I've walked the full circle on the surface and again found nothing.
I guess he is buried somewhere underground, but the planet is huge! Are there any tricks to find him quickly?