Board Thread:Questions and Answers/@comment-48285-20160610171807/@comment-4932025-20160610174456

We see 10 limbs on the spider, I don't think Chrollo counts as a limb so there might be a second member we don't know of.

Abegane would be really boring and Hisoka bait, he's just an exorcist and doesn't fit in with the Phantom troupe mentality.

As for who I think it is, Gyro, what better way to get the final villain into the story than through the Phantom troupe. though I don't think he'd be in there for long knowing his personality and how he wants to spread evil, he wouldn't get along with them, he's probably either gonna ditch the troupe real fast and/or backstab them, an encounter between Hisoka and Gyro would be interesting as they both have significant plot armor.