A Hell Talon is a single model. It is equipped with a helstorm cannon, a twin lascannon and a cluster of pyrax incendiary bombs.
The Hell Talon is the Chaos Space Marines' heavy fighter-bomber. Like the Hell Blade, it is made by the heretical Forge World of Xana from souls, flesh, metal, and daemons (or so the Imperium surmises -- considering that they disintegrate on destruction, it's hard to be sure). You'd think the Imperium would send a Kill Ship to destroy Xana (and any other Chaos Forge World they know of). But no, that wouldn't be grimdark enough and, additionally, most Dark Mechanicum Forge Worlds are basically daemon worlds, which give zero fucks about Exterminatus.