The Hounds were first introduced in Uncanny X-Men, from the "Days of Future Past" dystopian timeline, as part of the backstory of Rachel Summers.
[1] Shadow King is later seen to use mind-controlled humans called Hounds to track Storm, who had been transformed into a child by the villainous Nanny.
[2] Adrian Toomes is recruited into working at an Orchis black site, in order to track the movement of Nightcrawler through New York, bemoaning the audacity of mutantkind.
Toomes then reveals that his new title is "Director Vulture," before showing off his upgraded Phalanx-enhanced cybernetic wings, making the often weak villain now an incredibly formidable threat.
[3] Upon obtaining Cloak and Dagger, he adds them to the Hounds and sends them with Feral, Fatale, Animax, and Reaper to target Mystique and Nightcrawler's Creepy Crawler appearance.
They consist of Sable, Fireheart, Kravinoff, five different Vultures, the Scorpion, the Rhino, Hammerhead, Ox, a Hobgoblin, and various Green Goblins.
Reilly defeats them with the aid of Spider-Ham and the Old Man Spider-Man of Earth-4[7] Verna, Rhino, and Scorpion arrive to hunt Hobgoblin (who was the identity of this world's Peter Parker) and drain his life force.