* SPOILER ALERT * scroll down at your own caution
They helped him bury Undertaker, and some other stuff if you haven't read the spoilers for SD. even though Kane did attack them, it doesn't matter. He could still be behind it.
Kane's storyline is to bypass the Undertaker's legacy. He can say that Undertaker was the leader of a group call the ministry and Kane started Nexus so he can have his own group and be bigger than the Ministry. It's kinda like HBK/Angle rivalry from 05. Angle was trying to do everything HBK did, he sang his entrance song, won a ladder match (medal on the line) etc...
Undertaker had bearer on his side, Now Kane has bearer
Undertaker had ministry, Now Kane has Nexus
Undertaker had the title, Now Kane has the title.
It does have logic and maybe Kane is the one behind Nexus?
Maybe later on they can bring back the Ministry to feud with Nexus?
Pretty sure they can give Gangrel & Viscera short term contracts. Also have Big Show, Edge & Christian join in so it just doesn't seem that odd along with Undertaker, maybe even HHH and Vince.
After all he did help Otunga stay in Nexus