I think the sirens feed him with their kills, so maybe only the ones they kill go to Cade's hell? That's one way to make it fit with canon, I guess.
Hot guys + dark subject matter + plenty of violence = watchable television.

And they forgot that werewolves can byte vampires - look at Tyler , bleah. This season sucks. And even the actors are all bored. Look at Caroline and Stefan, they don't match anymore, they are struggling to act "in love".

assume they don't know either or care because these people are numbnuts when it comes to recalling their own lore, this is the same crack team that gave us werewolves who cant be turned only born as such then introduced a royal line of werewolves that date back to the first of their kindjust as does the genealogy or every werewolf ever introduced, who also forgot vampire can apparently control fog and crows and such.

Katherine is too awesome and can't be bothered with a lowly Other Side. She probably occupies an executive position within hell; therefore she enjoyed special treatment and went directly there.

"Art is magic delivered from the lie of being truth"

Either way point is she should have went to the other side it was still there

Katherine had used Traveler magic to took over Elena's body ,when she died she was a witch .

What about Katherine though? She was human when she died but she's a doppleganger so that means she's still a supernatural being.

Given how Silas and other ended when the OS broke down, I'd say Qetsiyah created a filter that caught supes before they could be sucked into Arkadius' realm.

"Art is magic delivered from the lie of being truth"

We don't know Cade's power so as of now it's up in the air.
The world is quiet here.