Without the empowerment of his Cave Heaven, his power had been reduced drastically. In fact, mortals are now faster than he is. So even with the constant activation of Divine Metacs to increase his speed, it still took him 8 days to reach his destination.
When he reached the location of the mark, he saw a metal dog waiting there for him. The spirit creatures around the area hadn't eaten this metal dog because it possessed only the law fragments of the Forging Pathway. He was sure that if he had sent a golem or metal puppet, it would be gone by now.
The metal dog was looking into an empty space. If Loki couldn't sense his mark, he wouldn't have known that there was anything to look at.
In fact, even with him sensing the mark, he still couldn't touch the Cave Heaven. His body passed through the place unhindered as he walked back and forth, trying to touch his prize.
