there hasnt been any sign of a new champ in a while

There's been at least 3 literal signs for Kled. Riot's been posting wanted signs/missing signs at cons and events written by a Noxian named Kled, looking for his lizard mount. There are also in-game teasers, with a rustling and animal screech noises when you walk by certain bushes.

Poster 1, found about 2 weeks ago, translated: https://1.bp.blogspot.com/-QkD5K08EIEA/V4GdUJfP3nI/AAAAAAAA8b4/Y-VTDFOTaG8RN4f-khbd2Az4kVeRfTfsgCLcB/s320/Cm9Z6fmWAAAz0Ky.jpg Poster 2, found last week, translated: https://3.bp.blogspot.com/-PytXQ9ag9dA/V4VMPtIxyFI/AAAAAAAA8hA/xTL5Ud9dYeEQVe67ljVAhSPYOp7Imv2mwCLcB/s360/hrtr.jpg Poster 3, found this week, in English: https://1.bp.blogspot.com/-Un7fwfOYhIk/V4lZKWZUJXI/AAAAAAAA8sU/nBAp6EAL9UIc3NO6yYs03IzqUnXGlbQKACLcB/s1600/asdasdsada.jpg

Also, the assassin update isn't even remotely close to being worked on. Yorick is currently being worked on, and the assassin update won't release until after him, once the season is over.