With the leaks by AutismGaming420, we are able to learn more details about the bloodhound skin that was teased in the Apex Legends videos recently.
Bloodhound skin will unlock levels once you have the following:
Tier 2 Deal 30,000 damage as bloodhound
Tier 3 Deal 100,000 damage as bloodhound
Finisher is unlocked with the 100,000 damage also.
The skin will be unlocked if you purchase all the event items like heirlooms in the past or you can get it from the new Mythic store which just appears to be the heirloom store renamed. We assume it would cost heirloom shards at the same price as an heirloom.