A Boss-tier Pet Egg was a Pet Egg dropped by a Boss after getting defeated. Without a doubt, the Pet that would be hatched from that sort of Egg would definitely have much higher Attributes than those from a normal Egg. And that was exactly why Slayer's Heart and his members had their eyes set on the idea of bonding with one. Between the quicker hatching of a normal Egg and the slower one of a Boss-tier Egg, they chose the latter hands down as the results would be a lot more satisfying.
But it was easier said than done.
